X = 2y - 7
4x + y = 71

(15, 11)

Step-by-step explanation:

(I'm assuming you are solving for x and y.)

Plug in the x equation:

4(2y - 7) + y = 71

8y - 28 + y = 71

9y - 28 = 71

9y = 99

y = 11

Then plug that answer into the other equation:

x = 2(11) - 7

x = 22 - 7

x = 15

You can check by doing the following to make sure you are right:

15 = 2(11) - 7

15 = 22 - 7

15 = 15

4(15) + 11 = 71

60 + 11 = 71

71 = 71