When do you use each method?

Substitution

Elimination

Graphing

You would use substitution when you are given a variable that is already solved.

ex. X= 7y+8

A good time to use elimination is when both equations are in standard form, and two variables are the same number, but opposite signs.

ex. 4x + 7y=8
-4x+8y=7

The best time to use graphing is when both equations are already in slope intercept. This makes it easy to plug into the calculator.

ex. Y= 4x+8
Y=8x+4