# How do you solve #y=x-4# and #y=2x# using substitution?

##### 3 Answers

#### Explanation:

We know that

This must mean that

By solving,

Now we know that

the value of

#### Explanation:

given equations are

put

#### Explanation:

Substitution means plugging one equation to another to solve for a variable, so:

Let's plug

By plugging it in, you get

Move variables to one side and constants in another

Since we found x, we can find y by plugging x back into either equations. Answer would be the same. To prove this, I'll plug x into both equations.

So,