Grade 8 · Unit 5Topic 2 of 2~24 min

Solving Systems Algebraically

Use substitution or elimination for exact answers.

Step 1 · Learn

Walkthrough

Read this first — it covers the idea in plain language with a worked example.

Worked example

Solve y = x + 1 and 2x + y = 7.

Elimination

If you line up the equations, you can add or subtract them to cancel a variable — handy when nothing is solved for y yet.

Step 2 · Watch

Watch the main video, then check the second take if you want another explanation.

Khan Academy

Substitute one equation into the other to solve.

Khan Academy

Add or subtract equations to eliminate a variable.

Step 3 · Practice

Try a worksheet or work through some problems before the quiz.

Step 4 · Check

A couple of questions to make sure this topic stuck. Retake as many times as you want.

Solving Systems Algebraically

Medium

Solve the system y = 2x and x + y = 9.