Question

Question 3(Multiple Choice Worth 4 points) (08.06) An unknown number y is 10 more than an unknown number x. The number y is also x less than 3. The equations to find x and y are shown below. y = x + 10 y = −x + 3 Which of the following statements is a correct step to find x and y?

Add the equation to eliminate x.
Multiply the equations to eliminate y.
Write the points where the graphs of the equations intersect the x-axis.
Write the points where the graphs of the equation intersect the y-axis.

Answer 1

Add the equation to eliminate x.

Explanation:

Add the equation to eliminate x.

Let's actually do the work!

y = x + 10

y = −x + 3

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

2y = 13, so y = 6.5.

Subbing 6.5 for y in either of the equations above lets us calculate y. For example, in the second equation, 6.5 = -x + 3, or 3.5 = -x, or x = -3.5.

The solution is (-3.5, 6.5).

Answer 2

Add the equations to eliminate x

Explanation:

Let's go through each of these statements

1) Add the equations to eliminate x

y = x + 10

+

y = -x + 3

_______

2y = 13

This works!