Math Practices and Problem Solving
13. Algebra In the first 3 months of the year,
an electronics store sold 1,446 cameras.
How many cameras did the store sell in March?
Write and solve an equation.

Answer:

x < -5

Step-by-step explanation:

3 ( -2x - 4 ) > 18

→ Expand the brackets

-6x - 12 > 18

→ Add 12 to both sides

-6x > 30

→ Divide both sides by -6

x < -5

Answer:

[tex]\boxed {\boxed {\sf x< -5}}[/tex]

Step-by-step explanation:

We are asked to solve the following inequality for x.

[tex]3(-2x-4) > 18[/tex]

Solve for x by isolating it and performing the inverse operations.

3 is being multiplied by (-2x-4). The inverse operation of multiplication is division. Divide both sides of the inequality by 3.

[tex]\frac {3(-2x-4)}{3} > \frac{18}{3}[/tex]

[tex](-2x-4) > \frac{18}{3}[/tex]

[tex]-2x-4 > 6[/tex]

4 is being subtracted from -2x. The inverse operation of subtraction is addition. Add 4 to both sides of the inequality.

[tex]-2x-4+4 > 6+4 \\[/tex]

[tex]-2x > 10[/tex]

x is being multiplied by -2. The inverse operation of multiplication is division. Divide both sides by -2.

[tex]\frac {-2x}{-2} > \frac {10}{-2}[/tex]

[tex]x> \frac {10}{-2}[/tex]

Since we divided by a negative number, the inequality sign must be flipped.

[tex]x< \frac{10}{-2}[/tex]

[tex]x < -5[/tex]

Answer:

it'd be d: 13/50 !!

Answer:

D. 13/50

Step-by-step explanation:

0.26 ⇔ 26/100 ⇔ 13/50

Answer:

88 ft

Step-by-step explanation:

Let's say the shortest piece has length 2x, so the medium piece has length 5x and the longest piece has length 8x. Added together, they equal 165, so

2x + 5x + 8x = 165

15x = 165

divide both sides by 15 to isolate x

x = 11

8x = longest piece = 88 ft

Step-by-step explanation:

12/14= 85.7143% 19/24= 79.1667%

Hope it helps.

Don't forget to click the Brainliest button if you like my answer and if you have any query, feel free to ask in the comment section.

Answer:

  x > 23/6

Step-by-step explanation:

Solve this one the same way you would a 2-step linear equation.

  6x +3 > 26 . . . . . given

  6x > 23 . . . . . . . . subtract the unwanted constant from both sides (step 1)

  x > 23/6 . . . . . . . .divide both sides by the coefficient of x (step 2)

__

Additional comment

If the coefficient of the variable in a 2-step linear inequality is negative, then the inequality symbol must be reversed when dividing by that negative number.

Answer:

P(X ≤ 46 | X~B(821, 0.078)) = 0.00885745584

0.00885... < 0.01

The test statistic of 46 is significant

There is sufficient evidence to reject H₀ and accept H₁

Air bags are more effective as protection than safety belts

Step-by-step explanation:

821 crashes

46 hospitalisations where car has air bags

7.8% or 0.078 probability of hospitalisations in cars with automatic safety belts

α = 0.01 or 1% ← level of significance

One-tailed test

We are testing whether hospitalisations in cars with air bags are less likely than in a car with automatic safety belts;

The likelihood of hospitalisation in a car with automatic safety belts, we are told, is 7.8% or 0.078;

So we are testing if hospitalisations in cars with air bags is less than 0.078;

So, firstly:

Let X be the continuous random variable, the number of hospitalisations from a car crash with equipped air bags

X~B(821, 0.078)

Null hypothesis (H₀): p = 0.078

Alternative hypothesis (H₁): p < 0.078

According to the information, we reject H₀ if:

P(X ≤ 46 | X~B(821, 0.078)) < 0.01

To find P(X ≤ 46) or equally P(X < 47), it could be quite long-winded to do manually for this particular scenario;

If you are interested, the manual process involves using the formula for every value of x up to and including 46, i.e. x = 0, x = 1, x = 2, etc. until x = 46, the formula is:

[tex]P(X = r) = nCr * p^{r} * (1 - p)^{n - r}[/tex]

You can find binomial distribution calculators online, where you input n (i.e. the number of trials or 821 in this case), probability (i.e. 0.078) and the test statistic (i.e. 46), it does it all for you, which gives:

P(X ≤ 46 | X~B(821, 0.078)) = 0.00885745584

Now, we need to consider if the condition for rejecting H₀ is met and recognise that:

0.00885... < 0.01

There is sufficient evidence to reject H₀ and accept H₁.

To explain what this means:

The test statistic of 46 is significant according to the 1% significance level, meaning the likelihood that only 46 hospitalisations are seen in car crashes with air bags in the car as compared to the expected number in car crashes with automatic safety belts is very unlikely, less than 1%, to be simply down to chance;

In other words, there is 99%+ probability that the lower number of hospitalisations in car crashes with air bags is due to some reason, such as air bags being more effective as a protective implement than the safety belts in car crashes.

Answer:

To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. For example 0.54+0.27 and 0.24 +0.57, If we know the value of our variables, we can replace the variables with their values and then evaluate the expression.

hope this helps.

Answer:

First, let's look at some polynomials of even degree (specifically, quadratics in the first row of pictures, and quartics in the second row) with positive and negative leading coefficients:❤

Answer:

The answer is C

Step-by-step explanation:

(I'm not completely sure)

Answer:

$35.64

Step-by-step explanation:

9 x 3.96 is 35.64

multiply 9 by 3, then 0.96 and add those answers together.

Answer: 35.64 dollars is your answer

Answer:

79 inches

Step-by-step explanation:

1 foot equals 12 inches

6 feet = 6*12 = 72 inches

72+7=79

79 inches

Answer:

π/10

Step-by-step explanation:

α=-19π/10=-19π/10+2π=(-19π+20π)/10=π/10

Answer:

725.623

Step-by-step explanation:

547.40:?

43 :57

?=547.40×57÷43

Answer:

  see attached

Step-by-step explanation:

The one that matches the triangle shown in the attachment has the given vertices.

Answer:

Step-by-step explanation:

When it's clear, the easiest way to do the problem is to used the x and y  intercepts.

This question is one of the clear one.

The x intercept is 2,0

The y intercept is 0,1

You want the slope.

m = (y2 - y1)/(x2 - x1)

y2 = 1

y1 = 0

x2 = 0

x1 = 2

m = (1 - 0)/(0 - 2)

m = 1 / -2

m = -1/2

In this case the slope and gradient have the same value --   - 1/2 or - 0.5

Answer:

4/3 1.333 1 1/3

Step-by-step explanation:

Answer:

so 2/3X 3/5 + 3

10 + 9 / 15 by LCM method

so 19/15 + 3 = 19/15 + 45/15 = 64/15

hope it helps

Step-by-step explanation:

Answer:

3 2/5

Step-by-step explanation:

2/3 (3/5) + 3

Multiply

6/15 + 3

Reduce fraction

2/5 + 3 = 3 2/5

Using the together rate, it is found that:

The together rate is the sum of each separate rate.

In this problem, we have that:

Applying the together rate:

[tex]\frac{1}{x} + \frac{1}{x + 3} = \frac{1}{2}[/tex]

[tex]\frac{x + 3 + x}{x(x + 3)} = \frac{1}{2}[/tex]

[tex]4x + 6 = x^2 + 3x[/tex]

[tex]x^2 - x - 6 = 0[/tex]

Which is a quadratic equation with coefficients [tex]a = 1, b = -1, c = -6[/tex], hence:

[tex]\Delta = b^2 - 4ac = (-1)^2 - 4(1)(-6) = 25[/tex]

[tex]x_1 = \frac{-b + \sqrt{\Delta}}{2a} = \frac{1 + \sqrt{25}}{2} = 3[/tex]

[tex]x_2 = \frac{-b - \sqrt{\Delta}}{2a} = \frac{1 - \sqrt{25}}{2} = -2[/tex]

We are interested into the positive root, then [tex]x = 3[/tex], [tex]x + 3 = 6[/tex], which means that:

You can learn more about the together rate at https://brainly.com/question/25159431

Answer:

Step-by-step explanation:

Let x be the adjacent side length in cm

opposite side is x + 2 cm

hypotenuse is x + 4 cm

x² + (x + 2)² = (x + 4)²

x² + (x² + 4x + 4) = (x² + 8x + 16)

x² - 4x - 12 = 0

(x - 6)(x + 2) = 0

so either

x - 6 = 0    x = 6

or

x + 2 = 0    x = -2

positive answer is x = 6 as negative length does not make sense

opposite side is 6 + 2 = 8

hypotenuse is 6 + 4 = 10

perimeter is 6 + 8 + 10 = 24 cm

Answer:

15 lessons for $ 80

Step-by-step explanation:

In case 1

Cost of 1 lesson = $10

In case 2

Cost of 1 lesson = 40/5 = $8

In case 3

Cost of 1 lesson = 80/10 = $8

In case 4

Cost of 1 lesson = 80/15 = $ 5.33

Hence,

The best deal is case 4 i.e 15 lessons for $ 80

Answer:

A year but -1.

Step-by-step explanation:

52x7=364.

Hope this helps!

Answer:

there are 364 days in 52 weeks.

Step-by-step explanation:

To find out how many days are in 52 weeks you have to multiply the amount of days there are in a week by 52, there are 7 days in a week and 7 times 52 is 364 so the answer is 364

the inequality is 8 (w+18) ≤ 19

Answer: -15.625

Step-by-step explanation:

Let w represent the number:

8 (w + 18) ≤ 19

[tex]\frac{8\left(w+18\right)}{8}\le \frac{19}{8}[/tex]

[tex]w+18\le \frac{19}{8}[/tex]

[tex]w+18-18\le \frac{19}{8}-18[/tex]

[tex]w\le \:-\frac{125}{8}[/tex]

-125/8 or -15.625

Check:

[tex]8\left(-15.625+18\right)\le \:19[/tex]

[tex]8\cdot \:2.375 \leq 19[/tex]

[tex]19 \leq 19[/tex]

Therefore, the number is -15.625

Answer:

For this answer, you need to do a conversion from pounds to grams. 1 pound is equal to 453.592 or just 453.6 grams if rounding is allowed. You would need to multiply 1.25 pounds to the 453.6 grams which would equal 566.99 grams or if you are rounding then it is 567 grams.

Your final answer is 567 grams of sugar.

Step-by-step explanation:

please mark me as brainlest

Answer:

31.25

Step-by-step explanation:

Divide 250 by 8=31.25

first you have to pick any two points on the line

(-3,4) and (0,-2)

then you subtract the y values

-2-4= -6

after that you subtract the x values

0 - (-3)= 3

the slope is -6/3, or -2