### Home > CCA2 > Chapter 7 > Lesson 7.1.2 > Problem 7-23

7-23.

Solve the system of equations shown below. Homework Help ✎ *x* + *y* + *z* = 40

*y* = *x* − 5

*x* = 2*z*

Use substitution to solve.

If *x* = 2*z*, then *y* = 2*z* − 5.

Now that you have expressions for both *x* and *y* in terms of *z*, substitute them into the first equation and solve for *z*.

Then solve for *x* and *y*.