# How do you solve the following system?: # x + 2y = -2 , y=2x+9 #

##### 1 Answer

#### Answer:

Substitution Property

#### Explanation:

If

Allow me to explain.

Replacing

Distribute:

Simplify:

Since we know what

Simplify

Also, just as a general rule of thumb, if you're unsure of your answers in any system of equations like this, you can check your answers by plugging both x and y into both equations and seeing if a valid input is spit out. Like so:

Since

Hence it is verified that