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2 years ago

By which number -7÷25 should be divided to get -1÷15

Mathematics

1 answer:

fredd [130]2 years ago

3 0

Answer:

Step-by-step explanation:

Set it up like an equation first:

$\frac{\frac{-7}{25} }{x}=-\frac{1}{15}$ and then bring up the lower fraction, flip it, and multiply:

$-\frac{7}{25}*\frac{1}{x}=-\frac{1}{15}$

Simplify to

$-\frac{7}{25x}=-\frac{1}{15}$ and cross multiply to get

-25x = -105 and divide both sides by -25 to get that

$x=\frac{105}{25}=\frac{21}{5}$

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Please help me, thank you

Alenkinab [10]

Problem 1

Answer: C) No solution

---------------------------

Explanation:

We have z = -4 and 4z = -4 at the same time. Solving 4z = -4 leads to z = -1

So in effect we have z = -4 and z = -1 at the same time, but this is a contradiction. A variable can only hold one number at a time.

======================================================

Problem 2

Answer: C) Infinitely many solutions

---------------------------

Explanation:

The two equations are equivalent. You can prove as such by isolating 2y in the first equation.

5x = 8-2y

5x+2y = 8

2y = 8-5x

2y = -5x+8

-5x+8 = 2y

This shows the first equation is equivalent to the second, and vice versa. They both graph the same line. Any point along the line is a solution. So that's why there are infinitely many of them.

======================================================

Problem 3

Answer: Choice A) $-6 < y \le 3$

---------------------------

Explanation:

The range is the set of the possible y values. We're concerned with every y coordinate of each (x,y) solution. So we only focus on the shaded region.

The dashed line means we exclude the boundary. It's an electric fence we cannot touch. So y > -6 or -6 < y describes part of the range

The other part is $y \le 3$ since y = 3 is the when the highest point occurs.

So writing $-6 < y \le 3$ describes all possible y values of each (x,y) solution in the shaded region.

6 0

4 years ago

What is the solution to this system of equations?<br> 5x + 2y = 29<br> x + 4y= 13

Readme [11.4K]

Answer:

x = 4.5

y = 3.25

Step-by-step explanation:

Use elimination

5x + 2y = 29

x + 4y = 13 (-5)

4y(-5) = 13(-5)

2y = 29

-20y = -65

y = 3.25

Sub it back into the equation

5x + 6.50 = 29

5x = 22.5

x = 4.5

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3 years ago

Free cheat!!!!division!!

In-s [12.5K]

Answer:

3/2 3*5=15

3/2=1.5

Step-by-step explanation:

8 0

3 years ago

/viewform?hr submission=Chclk4feKBIQ.

Gennadij [26K]

Answer:

c) .22

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

In this question:

$\sigma = 2.5, n = 500$

Then

$M = z*\frac{\sigma}{\sqrt{n}}$

$M = 1.96*\frac{2.5}{\sqrt{500}}$

$M = 0.22$

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4 years ago

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Arturiano [62]

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3 years ago