Question

Solve the following system of equations by substitution. Make sure to check your solution. x + y = 5 3x - y = -5

Answer 1

(0.5)

Explanation:

x + y = 5

3x - y = -5

Put "y" on one side to isolate

3x - y = -5

3x = y - 5

3x + 5 = y

Plug "3x + 5" in for "y" in the second equation

x + (3x + 5) = 5

4x + 5 = 5

4x = 0

x = 0

Plug "0" in for "x" in any one of the equations

0 + y = 5

y = 5

To check, plug in "0" for "x" into the first equation and make sure they get the same answers

3(0) - y = -5

0 - y = -5

y = 5

Answer 2

First pick one that turns out to be a positive or negative