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Systems of equations with substitution: potato chips

To solve a system of equations using substitution...

1. Isolate one of the variables in one of the equations, e.g. rewrite 2x+y=3 as y=3-2x.
2. You can now express the isolated variable using the other one. *Substitute* that expression into the second equation, e.g. rewrite x+2y=5 as x+2(3-2x)=5.
3. Now you have an equation with one variable! Solve it, and use what you got to find the other variable.

Created by Sal Khan.

Video transcript