Solving a System of 3 Equations with 3 Unknowns

Breakdown Step 1 Labeling Step 2 Reduce to a 2 by 2 Step 3 Substitute Back In Step 4 Check Solution

Step 1- Labeling E1 E2 E3 Label your original equations with something easy so you can reference them as you plan each step of the problem. The order does not matter as long as you are consistent.

Step 2 – Reduce to a 2x2 Choose two equations and use elimination to eliminate one variable, then eliminate the same variable using a choice of two other equations. Label each step and label your new equations. (E1* and E2*) E1 + -3(E2) = E1* 4(E2) + E3 = E2*

Step 2 – Reduce to a 2 by 2

Solve the 2 by 2

Step 3 – Substitute Back In E1*

Substitute Back In E1

Step 4 - Check Solution E3