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4 years ago

Solve the system of linear equations by elimination 2x+7y=1 2x-4y=12

1 answer:

3 0

$\left\{\begin{array}{ccc}2x+7y=1\\2x-4y=12&\text{change the signs}\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}2x+7y=1\\-2x+4y=-12\end{array}\right}\qquad\text{add both sides of equations}\\.\qquad\qquad11y=-11\qquad\text{divide both sides by 11}\\.\qquad\qquad \boxed{y=-1}\\\\\text{Put the value of y to the first equation:}\\\\2x+7(-1)=1\\2x-7=1\qquad\text{add 7 to both sides}\\2x=8\qquad\text{divide both sides by 2}\\\boxed{x=4}\\\\Answer:\ \boxed{x=4\ and\ y=-1\to(4,\ -1)}$

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7 0

4 years ago

Read 2 more answers

3. Given the directed line segment AB, with endpoints A20, 6) and B(-16, 50), find the point Q

garri49 [273]

The point Q that partitions the line segment is Q(2,28)

Given that the directed line segment AB, with endpoints A(20, 6) and B(-16, 50) and divide the segment into a 1:1 ratio.

A line segment is a part of a line bounded by two distinct endpoints and containing all the points of the line segment between its endpoints.

We will find the point Q by using the section formula that is

Q(x,y)=((mx₂+nx₁)/(m+n),(my₂+ny₁)/(m+n))

The given ratio is m:n=1:1 and the points (x₁,y₁)=(20,6) and (x₂,y₂)=(-16,50).

Firstly, we will find the point Q for x-axis, we get

Q(x)=(mx₂+nx₁)/(m+n)

Q(x)=(1×(-16)+1×20)/(1+1)

Q(x)=(-16+20)/2

Q(x)=4/2

Q(x)=2

Now, we will find the point Q for y-axis, we get

Q(y)=(my₂+ny₁)/(m+n)

Q(y)=(1×50+1×6)/(1+1)

Q(y)=(50+6)/2

Q(y)=56/2

Q(y)=28

The point Q that partitions the line segment is Q(x,y)=(2,28)

Hence, point Q partitions this segment into a 1:1 ratio with directed line segment AB, with endpoints A(20, 6) and B(-16, 50) is Q(2,28).

Learn more about the line segment from here brainly.com/question/9034900

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2 years ago

Match the new coordinates that define the figure after dilation with a center at the origin by the given scale factor.

Lemur [1.5K]

Answer:

Step-by-step explanation:

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7 0

3 years ago

Please help! I don't understand how to solve this problem

Ilia_Sergeevich [38]

Using the z-distribution, a sample of 142,282 should be taken, which is not practical as it is too large of a sample.

<h3>What is a z-distribution confidence interval?</h3>

The confidence interval is:

$\overline{x} \pm z\frac{\sigma}{\sqrt{n}}$

The margin of error is:

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

In which:

$\overline{x}$ is the sample mean.

z is the critical value.

n is the sample size.

$\sigma$ is the standard deviation for the population.

Assuming an uniform distribution, the standard deviation is given by:

$S = \sqrt{\frac{(4 - 0)^2}{12}} = 1.1547$

In this problem, we have a 95% confidence level, hence $\alpha = 0.95$ , z is the value of Z that has a p-value of $\frac{1+0.95}{2} = 0.975$ , so the critical value is z = 1.96.