Solve a System of Equations Using Substitution
Substitution replaces one variable with an equivalent expression.
Do this: Read the concept below, then try the quiz or activity.
Lesson 137 of 188
72%
Concept
Steps: 1. Solve one equation for one variable. 2. Substitute into the other equation. 3. Solve for the remaining variable. 4. Back-substitute to find the other variable.
Example: y = x + 2 2x + y = 11 Substitute: 2x + (x + 2) = 11 3x + 2 = 11 3x = 9 -> x = 3 y = 3 + 2 = 5 Solution: (3,5)
Try it
Practice: Solve a System of Equations Using Substitution.