Solving System of Linear Equations by Elimination

I can explain, orally and in writing, how I solved a system using elimination, using

vocabulary like “eliminate,” “coefficient,” and “solution.”

​LANGUAGE OBJECTIVE

I can use elimination to solve a system of linear equations.

​CONTENT OBJECTIVE

The additive inverse of a number is the value that you add to it to get zero.

👉 In other words:

A number and its additive inverse always add up to 0.

Definition

If a number is a, then its additive inverse is −a.

Example:

5 + (-5) = 0 -15 + 15 = 0

1. Eliminate one variable
   Add or subtract the equations (multiply first if needed) so one variable cancels out.

2. Solve for the other variable
   Solve the equation you get after eliminating a variable.

3. Substitute and check
   Put that value into one of the original equations to find the other variable and check your solution.