The substitution method solves a system of equations by rearranging one equation for a variable and putting that expression into the other. It works best when one variable already has a coefficient of 1.
Math Dictionary / Substitution Method
Substitution Method
The substitution method solves a system by replacing one variable with an equivalent expression.
AlgebraGrade 8Algebra 1GEDSATACT
What it means
It is useful when one equation is already solved for a variable.
Also called: substitution
Examples
| If y = x + 2, replace y in the other equation with x + 2 |
| Solve for one variable first |
| Then substitute back |
Common mistake
After finding one variable, substitute back to find the other.
Try one
Question: If y = x + 1 and x = 4, what is y?
Show answer
5.