How do you decide which variable to substitute when solving with substitution

You can substitute any variable you want, but it's best to look for the one that is the least work for you.

Some systems of equations already have a variable alone on one side, making it really easy to substitute them into the other one.

In that case, you would want to use that variable because the first step has already been done for you. It saves time.

brainiest?

Step-by-step explanation: