Question 61 point)

PLS HELP IM FAILING MATH!

oksano4ka [1.4K]

Answer:

1. Never true

2. Never true

3. Bad question! Typo? (see discussion below)

4. Always true

5. Always false

Step-by-step explanation:

1. x - 13 = x + 1. Subtract x from both sides of the equation, and you get -13 = 1. False! (Never true!)

2. x + 1/2 = x - 1/2. Subtract x from both sides: 1/2 = - 1/2. False! (Never true!)

3. This one's weird, with two equal signs. That's not unusual; multiple equal signs are often used when a chain of equalities is being displayed. For instance, you can write (3)(2x + 5) = (3)(2x) + (3)(5) = 6x + 15. That's an example of the Distributive Property--the 3 is multiplied by both of the terms inside parentheses (shown after the first equal sign), then actually doing those multiplications produces the expression after the second equal sign.

OK! This question says 2(x + 3) = 5x = 6 - 3x. Take it in two parts.

a. 2(x + 3) = 5x Distribute the 2.

2x + 6 = 5x Now subtract 2x from both sides.

6 = 3x Divide both sides by 3.

2 = x So that first part is true only when x = 2. Gaa! That's not one of your answer choices. Now, check out the second part

b. 5x = 6 - 3x Add 3x to both sides.

8x = 6 Divide by 8

x = 6/8 = 3/4

It doesn't help to use the first and third expressions, either.

2(x + 3) = 6 - 3x Distribute the 2

2x + 6 = 6 - 3x Add 3x.

5x + 6 = 6 Subtract 6.

5x = 0 Divide by 5

x = 0

None of these is always false. None of these is always true.

4. x - 3 = 2x - 3 - x Simplify the right side by combining the x terms.

x - 3 = x - 3 Aha! Same expression on both sides! Always true

5. 3(x - 5) = 2(x - 5) + x Distribute the 3. Distribute the 2.

3x - 15 = 2x - 10 + x Combine the x terms on the right.

3x - 15 = 3x - 10 Subtract 3x

-15 = -10 (Always false!)

7 0

2 years ago

A simple random sample of items resulted in a sample mean of . The population standard deviation is . a. Compute the confidence

Varvara68 [4.7K]

Answer:

(a): The 95% confidence interval is (46.4, 53.6)

(b): The 95% confidence interval is (47.9, 52.1)

(c): Larger sample gives a smaller margin of error.

Step-by-step explanation:

Given

$n = 30$ -- sample size

$\bar x = 50$ -- sample mean

$\sigma = 10$ --- sample standard deviation

Solving (a): The confidence interval of the population mean

Calculate the standard error

$\sigma_x = \frac{\sigma}{\sqrt n}$

$\sigma_x = \frac{10}{\sqrt {30}}$

$\sigma_x = \frac{10}{5.478}$

$\sigma_x = 1.825$

The 95% confidence interval for the z value is:

$z = 1.960$

Calculate margin of error (E)

$E = z * \sigma_x$

$E = 1.960 * 1.825$

$E = 3.577$

The confidence bound is:

$Lower = \bar x - E$

$Lower = 50 - 3.577$

$Lower = 46.423$

$Lower = 46.4$ --- approximated

$Upper = \bar x + E$

$Upper = 50 + 3.577$

$Upper = 53.577$

$Upper = 53.6$ --- approximated

So, the 95% confidence interval is (46.4, 53.6)

Solving (b): The confidence interval of the population mean if mean = 90

First, calculate the standard error of the mean

$\sigma_x = \frac{\sigma}{\sqrt n}$

$\sigma_x = \frac{10}{\sqrt {90}}$

$\sigma_x = \frac{10}{9.49}$

$\sigma_x = 1.054$

The 95% confidence interval for the z value is:

$z = 1.960$

Calculate margin of error (E)

$E = z * \sigma_x$

$E = 1.960 * 1.054$

$E = 2.06584$

The confidence bound is:

$Lower = \bar x - E$

$Lower = 50 - 2.06584$

$Lower = 47.93416$

$Lower = 47.9$ --- approximated

$Upper = \bar x + E$

$Upper = 50 + 2.06584$

$Upper = 52.06584$

$Upper = 52.1$ --- approximated

So, the 95% confidence interval is (47.9, 52.1)

Solving (c): Effect of larger sample size on margin of error

In (a), we have:

$n = 30$ $E = 3.577$

In (b), we have:

$n = 90$ $E = 2.06584$

Notice that the margin of error decreases when the sample size increases.

4 0

3 years ago

The table shows all the possible outcomes for spinning the pointer of the spinner with four equal sized sections labeled 1–4 and

vladimir1956 [14]

Answer:

12.5%

Step-by-step explanation:

There are two types of spinners here and the outcome of them is independent. That means

P(odd number,C) = P(odd number) * P(C)

There are two odd numbers out of four numbers in the first spinner. The chance of odd number will be:

P(odd) = 2/(2+2)= 1/2= 50%

There are four letters and the desired outcome is C. The chance for C will be:

P(C)= 1/4= 25%

Then the chance will be:

P(odd number,C) = P(odd number) * P(C)

P(odd number,C) =50% * 25% = 12.5%

5 0

2 years ago

Read 2 more answers

5. Katie makes and sells scarves. Her monthly profit is given by P(s) = -s2 + 25s - 100, where "s" is the selling price. For wha

Marat540 [252]

Answer: s > 5

Step-by-step explanation:

-s² + 25s - 100 > 0

Coefficient of s² is -1, multiply the equation through by -1.

-1 × (-s² + 25s - 100)

s² — 25s + 100

ax² + bx + c

Then you get the factors x and y that gives x + y = b and xy = c

b = -25 and c = 100, x = -20 and y = -5

-20 × -5 = 100 and -20 + -5 = -25

Then

s² — 20s — 5s + 100 > 0

Factorising,

s (s — 20) — 5(s — 20) > 0

(s — 5)(s — 20) > 0

(s — 5) > 0 and (s — 20) > 0

s>5 and s>20

s > 5

Hope this Helps?

4 0

3 years ago

What is the equation of the line

balandron [24]

Answer:

y=2x+2

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers