Why do scientists use models?
A)
Models are unreliable.
B)
Models waste natural resources.
Models predict not just describe events.
Models are based on scientific laws and principals so they are more
reliable than the real thing.
D)

Answers

Answer 1
The correct answer is A

Related Questions

17/6 + 4/3 fractions

Answers

Answer:

25/6

Step-by-step explanation:

I multiplied 4/3 by 2, so the new fraction is 8/6. You add 17/6 with 8/6, and you get 25/6. I hope you understand.

-5 ≤ -2; Add 7 to both sides

Help pls

Answers

Answer:

2 ≤ 5

Step-by-step explanation:

-5 ≤ -2 add 7 to both sides

-5+7 ≤ -2+7 calculate

2 ≤ 5

Help me little brother with his math please

Answers

Answer: less,less greater

Step-by-step explanation:

Answer: #1 : less than 930

Answer: #2 : less than 930

Answer: #3 : greater than 930

Hope this helps older sis!

Write 3 9/10 as an improper fraction.

Answers

Answer:

39/10

Step-by-step explanation:

Answer:

39/10

Step-by-step explanation:

to make 3 9/10 an improper fraction all you have to do is take the whole number-3 and take the denominator-10 and multiply them 3 x 10 = 30, then add it to the numerator 9 + 30 equals 39 this is your new numerator

Answer!
A car travels from A to B at a speed of 30 mph then returns, using the same road, from B to A at a speed of 65 mph. What is the average speed for the round trip?

Answers

Here is an example for your question



Average with respect to what? If we take the time-weighted average, the two legs of the trip will be weighted differently (the leg from A to B taking 60/40 = 3/2 times as long as the leg from B to A), and we will get an average of 48 MPH.

But the time-weighted average is not the only average we can consider. We could also consider the distance-weighted average (which might be useful if we were considering, say, the wear on the road caused by such travel); then the two legs would be weighted equally and the average would be 50 MPH.

Often, when people speak about average speed, it's the former of these notions which is implicitly meant (since speed itself is distance over time, we have the nice property that the time-weighted average of speeds will always be the total distance over the total time), but the latter is a perfectly legitimate notion as well. Averages are always averages with respect to some weighting, and different weightings will give different averages.

Answer:

         41 mph

Step-by-step explanation:

s₁ = s₂ = x       {the distance from A to B}

s = s₁ + s₂ = x + x = 2x      {the distance of the round trip}

t = t₁ + t₂               {the time of the round trip}

v₁ = 30 mph      

v₂ = 65 mph

t₁ = s₁/v₁ = x/30 h       {the time of trip from A to B}

t₂ = s₂/v₂ = x/65 h      {the time of trip from B to A}

The average speed:

[tex]v=\dfrac st=\dfrac{2x}{\frac x{30}+\frac x {65}}=\dfrac{2x}{x(\frac 1{30}+\frac1 {65})}=\dfrac{2}{\frac{13}{390}+\frac6{390}}=2\cdot\frac{390}{19}=41.05263...\approx41[/tex]

Find the value of x​

Answers

Answer: x= 108

Step-by-step explanation: The triangle is an isosceles triangle, so the two sides are parallel which means the other angle equals to 72 as well. Now we take the triangle rule and do 180-72-72= 36 (the top angle= 36). The triangles are all equal so that means the other angle (in the upside down one) also equals 72 so we take 36+72= 108. Since it is also a parallelogram, the angles are equal.

There are 96 crayons in a box. Janice takes 9 crayons. How many are left?​

Answers

Answer:

87

Step-by-step explanation:

Answer:

87 crayons

Step-by-step explanation:

96-9=87

If Z= 2+2i, what is z^4?

Answers

Answer:

D. 64 (cos(pi)+isin(pi))

Step-by-step explanation:

Put 2+2i into trigonometric form, raise the r value to the power of 4, and multiply the angle value (theta) by 4 to get the equation of z^4. In this case, r was 2(sqrt2), which raised to the 4th power was 64. The angle value was pi/4, which multiplied by 4 was pi. That's how we get the answer:

64 (cos(pi)+isin(pi)). How this helps!

Following are the calculation to the given value:

Given:

[tex]\to Z= 2+2i[/tex]

To find:

[tex]Z^4=?[/tex]

Solution:

[tex]\to Z= 2+2i[/tex]

[tex]\therefore\\\\i^2= -1[/tex]

[tex](a+b)^2= a^2+b^2+2ab[/tex]

Square the given value:

[tex]\to Z^2= (2+2i)^2[/tex]

         [tex]= 2^2+(2i)^2+2 \times 2 \times 2i\\\\= 4+4i^2+8i\\\\= 4-4+8i\\\\=8i[/tex]

When [tex]Z^2= 8i[/tex] then again square the value

[tex]\to ( Z^2)^2= (8i)^2\\\\\to Z^4= 64i^2\\\\\to Z^4= -64\\\\[/tex]

Therefore, the final answer is "-64".

Learn more:

brainly.com/question/25250313

Question 22 of 25
Which of the following are solutions to the quadratic equation below?
Check all that apply.
3x2 - 7x-3 = x
D A. 1
B. 3
] j
C. -3
D. -4
E.
=
1
O F..2

Answers

B and E. see attached

Plz answer these 2 I’ll mark brainliest

Answers

Answer:

16. C

17. B

sorry if i got it wrong

Answer:

THE ANSWER

A

B

Step-by-step explanation:

MARK BRAINLIEST

A statistics teacher announces to the class at the beginning of the semester that there is a 40% chance that a randomly chosen student will finish the semester with an A in the class and there is a 60% that a randomly chosen student will get an A on a test during the semester. Is the probability that a randomly chosen student receives an A in the class and an A on a test during the semester equal to 0.24? Yes, because the chance of getting an A on a test and getting an A in the class are mutually exclusive. Yes, because the chance of getting an A on a test and getting an A in the class are mutually exclusive. No, because the chance of getting an A on a test and getting an A in the class are not independent. No, because the chance of getting an A on a test and getting an A in the class are not independent. Yes, because the chance of getting an A on a test and getting an A in the class are independent. Yes, because the chance of getting an A on a test and getting an A in the class are independent. No, because the chance of getting an A on a test and getting an A in the class are not mutually exclusive.

Answers

Answer:

c. No, because the chance of getting an A on a test and getting an A in the class are not independent.

Step-by-step explanation:

brainly?

The regular price of a CD player is $89. It is on sale at a 25% discount. What is the sale price of the CD player?

Answers

Answer:

$66.75

Step-by-step explanation:

You would multiply $89 by .25 to find out what 25% is, then subtract that from $89 to get $66.75

Answer:

$66.75

Step-by-step explanation:

Help me ASAP pls with this

Answers

Answer:-15,20

Step-by-step explanation:

-15 and then 20 :) I hope this helps


f) Cosec2A + Cot4A = CotA – Cosec4A

Answers

Answer:

True (the sides are equal)

I hope this helps!

Bianca set the thermostat in her house to 87°F, which was 13° warmer than the temperature outside. What temperature was it outside?

Confused.

Answers

Answer: 74 degrees Fahrenheit  

Step-by-step explanation: the temperature outside was 13 degrees lower than 87 degrees, so  87 - 13 = 74

Answer:

74 degrees F

Step-by-step explanation:

Subtract the 87 - 13

This is because there are +13 degrees more than outside. So if you add 74 + 13 that were added by the thermostat, you get 87 degrees. Does it make sense?

Just subtract :)

Each of the numbers 0, 2, 4, 6, 8, 10, 12, and 14 is written on a separate sheet of paper and placed into a box. One piece of paper is selected at random. Find the probability that the piece of paper selected contains the number 8 or a number less than 12.

Answers

Answer:

For the second, all numbers less than 12, that would be 87.5%

Step-by-step explanation:

There are eight numbers. 100 divided by 8 is 12.5. 12.5 multiplied by 7 is 87.5.

What are the coefficients and constants of 7+5x need fast!!!!

Answers

Answer:

35

Step-by-step explanation:

there u go have a great day!

Factorize;Answer the tick one i will mark you as brainlist please quickly step by step explanation also please show it clearly i will mark you as brainlist​

Answers

Answer:

Solved only ticked ones

4a² + 49b² = (2a + 7b)² - 28ab = 11² - 28*2 = 654x² + 9y² = (2x + 3y)² - 12xy = 12² - 12*6 = 724x² + 9y² = (2x - 3y)² + 12xy = 2² + 12*8 = 10016x² + 25y² = (4x - 5y)² + 40xy = 6² + 40*8 = 356

Answer:

use the formula:

[tex]a {}^{2} + {b}^{2} = (a + b) {}^{2} - 2ab[/tex]

1) 4a² + 49b²

= 2²a² + 7²b²

= (2a)² + (7b)²

based on the formula above, a = 2a and b = 7b

= ( 2a + 7b )² - 2(2a)(7b)

substitute 2a+7b = 11 into the equation

= 11² - 2( 14ab )

= 121 - 28ab

substitute ab = 2 into the equation

= 121 - 28(2)

= 121 - 56

= 65

2) 4x² + 9y²

= 2²x² + 3²y²

= (2x)² + (3y)²

based on the formula, a = 2x and b = 3y

= ( 2x + 3y )² - 2(2x)(3y)

substitute 2x+3y = 12 into the equation

= 12² - 2(2x)(3y)

= 144 -2(6xy)

= 144 - 12xy

substitute xy = 6 into the equation

= 144 - 12(6)

= 144 - 72

= 72

3) 4x² + 9y²

= 2²x² + 3²y²

= (2x)² + (3y)²

= (2x)² - (-3y)²

based on the formula, a=2x and b=-3y

= ( 2x-3y )²- 2(2x)(-3y)

substitute 2x-3y = 2 into the equation

= (2)² - 2(2x)(-3y)

= 4 - 2( -6xy )

= 4 + 12xy

substitute xy = 8 into the equation

= 4 + 12(8)

= 4 + 96

= 100

4) 16x² + 25y²

= 4²x² + 5²y²

= (4x)² + (5y)²

= (4x)² - (-5y)²

based on the formula, a = 4x and b = -5y

= (4x-5y)² - 2(4x)(-5y)

substitute 4x-5y = 6

= (6)² -2(4x)(-5y)

= 36 -2(-20xy)

= 36 + 40xy

substitute xy = 8 into the equation

= 36 + 40(8)

= 36 + 320

= 356

Need help with this

Answers

Answer:

The value of x is 25

Step-by-step explanation:

A secant is a line that intersects a circle in exactly two points. When two secants, intersect at a point outside a circle then the measure of the angle formed between them is one-half the positive difference of the measures of the intercepted arcs

In the given figure

→ In circle O

∵ GB and GD intersect it at points F, B, and E, D

GB and GD are secants of circle O

∵ GB and GD intersect outside the circle O at point G

∵ They intercepted arcs EF and BD

→ By using the rule above

m∠G = [tex]\frac{1}{2}[/tex] (m arc BD - m arc EF)

∵ m arc BD = m arc BC + m arc CD

∵ m arc BC = 35° and m arc CD = 100°

m arc BD = 35 + 100 = 135°

m arc EF = x

m∠G = 55°

→ Substitute them in the rule above

55 = [tex]\frac{1}{2}[/tex] (135 - x)

→ Multiply both sides by 2 to cancel the fraction [tex]\frac{1}{2}[/tex]

∵ 110 = 135 - x

→ Subtract 135 from both sides

∴ -25 = -x

→ Divide both sides by -1

25 = x

The value of x is 25

ahhhh I need help please!!

Answers

Answer:

two teaspoons i think sorry if this doesnt help

Step-by-step explanation:

When we solve the inequality, will we keep or switch the inequality sign?

−2x>13


Keep

Switch

Answers

Answer:

switch I think cuz there is a negative

Step-by-step explanation:

Hope u have a nice day

Answer:

switch

Step-by-step explanation:

whenever u divide a number by a negative number across the inequality, the inequality sign switches

Collin is playing a video game. He wins 25 points for each gold coin he finds. His goal is to win more than 200 points. He wants to know how many gold coins he needs to find.

Answers

Answer:

200/25×1

=8 gold coins

Step-by-step explanation:

The required number of gold coins he needs is given 8 coins.

Given that,
Collin is playing a video game. He wins 25 points for each gold coin he finds. His goal is to win more than 200 points.

What is simplification?

The process in mathematics to operate and interpret the function to make the function or expression simple or more understandable is called simplifying and the process is called simplification.

Here,
1 coin = 25 points
For 200 points number of coins is given as = 200 / 25 = 8 coins

Thus, the required number of gold coins he needs is given 8 coins.

Learn more about simplification here:

https://brainly.com/question/12501526

#SPJ2


Solve the system of linear equations by substitution.
1/2x +y=-4
y = 2x + 16

Answers

sub 2x+16 for y into the 1st line so
1/2x+2x+16=-4 now find x
which is x=8 not plug in -8 for x, does not matter which one
you will get y=0
answer•
x=-8
y=0
(-8,0)

Answer:

y = 0

x = -8

Step-by-step explanation:

1/2x + y = - 4

y = 2x + 16

1/2x + (2x + 16) = - 4

1/2x + 2x = - 4 - 16

5/2x = -20

2/5 x 5/2x = -20 x 2/5

x = -40/5

x = -8

y = 2x + 16

y = 2(-8) + 16

y = -16 + 16

y = 0

Check:

1/2x + y = - 4

y = 2x + 16

1/2(-8) + (0) = -4

-4 + 0 = -4

-4 = -4

y = 2x + 16

(0) = 2(-8) + 16

0 = -16 + 16

0 = 0

What is the common factors of 9 and 67



Please don't google it

Answers

Answer:

1

Step-by-step explanation:

Answer:

1

Step-by-step explanation:

9 1, 3 9

67 1 and 67

so just enjoy ur day and have a great Christmas and new year

lemma get some help plz

Answers

Answer:

-2.6f -16

Step-by-step explanation:

add like terms -

-2.6 + 0.3 = -2.6f

and

-12-4 = -16

pls help this is due today!!! if correct I'll make Brainliest!!!!​

Answers

1= 1/8

2= 4/8

3= 2/8

Step-by-step explanation:

The probablity would be 3/4

A new pair of boots is priced at $123.75, plus 6% sales tax. What is the total cost of the boots?

Answers

Answer:

131.18

Step-by-step explanation:

Divide 2+1/2
A. 2
B. 16
C. 8
D. 4

Answers

4 because i know it is

Answer:

the answer would be 4, the number 2 would double since your dividing it by 0.5

can someone help me with the equation(s)

Answers

She purchased 8 sports drinks

{d=p+3

2.25p+1.25d=21.25

d=p+3

p=d - 3

2.25(d - 3) + 1.25d = 21.25

2.25(d-3) + 1.25d=21.25

2.25 - 6.75 + 1.25d = 21.25

3.5d = 21.25+6.75

d=28/3.5

D=8

a sandbox is in the shape of a right triangle. The two legs measure 9 inches and 16 inches. what is the perimeter of the sandbox?​

Answers

Answer:

Perimeter = 50 inches

Step-by-step explanation:

Use pythagoreon theorem to find the hypotenuse

a^2 + b^2 = c^2

3^2 + 4^2 = 5^2

9 + 16 + 25 = perimeter

perimeter = 50

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It's no wonder, then, that this ancient shark left so many of them behind. Without this trail of teeth, we would not know that these enormous creatures swam the ancient oceans as a top predator.Select two sentences from below that best show that the author wants the reader to be able to relate Megalodon's size to everyday life A.What would you expect a creature whose name means big tooth to look like?B.The Megalodon shark deserves this title.C.As the Greek roots mega- (big) and don (tooth) suggest, this awesome prehistoric creature certainly did have huge teethas well as a massive and powerful body.D.Scientists estimate that these gigantic sharks stretched as long as 60 feet.E.If you're having trouble imagining that, just think of a school bus, typically about 45 feet in length.F.Now, imagine a shark just a bit larger than that school buswith 7-inch teeth.G.Yes, this ancient fish certainly earned the prefix mega!H.Since these sharks are extinct, how do we know exactly how huge and powerful the Megalodon shark was? What is the climax of The Phantom Tollbooth? 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