### Home > A2C > Chapter 9 > Lesson 9.3.2 > Problem 9-151

9-151.

Multiply the second equation by −1 and add the two equations together.

2*x* + *y* = 10

− *x* − *y* = −25

*x* = −15

Use the *x*-value to calculate the *y*.

*y* − 15 = 25

*y* = 40

(−15, 40)

Solve the first equation for *y* and substitute it into the second.