# How do you solve #x= -2y+10# and #3x-y=9# using substitution?

##### 1 Answer

#### Explanation:

When solving systems of equations using the substitution method, the whole goal is to plug one equation into the other to find solutions for variables.

To do this, you want **at least one** of your equations in the system to be isolated for a variable. For example, compare your first and your second equations. Your first equation,

To begin, take your equation that has a variable isolated by itself in it (in your case, **substitute** in its place the expression

This means that for any equations in your system, you can substitute (

So, let's substitute (

Distribute the 3, combine like terms, and solve for the variable.

This gives you the answer to one of your variables. Now that you have a new expression **with an isolated variable**, you can **substitute** it back into either of your original equations to solve for the other unsolved variable.

Plug the answer you got (

You can check that the answers you got (

Plug 4 in for

Thus, we know that our answers are correct because we got a true statement in return. Hope this helps!