2x – 2y = -4 and x + y = 8

Question

System of equations:

2x – 2y = -4 and x + y = 8

Solve for x and y

Answer 1

Step #1 : Take the simpler equation and solve for X.

x + y = 8

-y -y

x = 8 - y

Step #2: Substitute the new X value into the remaining equation.

(This should give you the numeric value of y)

2(8-y) -2y = -4

16 -2y -2y = -4

16 -4y = -4

-16 -16

-4y = -20

-4 -4

y=5

Step #3: Plug the numeric value of Y into the simple equation to solve for X.

(This should give you the numeric value of X)

x + y = 8

x + 5 = 8

-5 -5

x = 3

Step #4: CHECK your answer by substituting the x and y value into the remaining equation

2x - 2y = -4

2(3) -2(5) = -4

6 - 10 = -4

-4 = -4