🎁 Free starter lesson · No signup required

Start Here: Solving a Linear Equation

A free 3-step lesson from Dr. E. Watch a short clip, walk through one worked example, then try a practice problem on your own. Nothing to install. No account to make.

Watch the lesson

A quick intro to how Dr. E breaks down a linear equation. Press play whenever you're ready.

Solving Linear Equations — Numberbender lesson with Dr. E

Worked example: solve 3x + 7 = 22

Linear equations have one variable. Your job is to isolate that variable using inverse operations — one step at a time.

3x + 7 = 22

Subtract 7 from both sides to undo the +7.

3x + 7 − 7 = 22 − 7 → 3x = 15

Divide both sides by 3 to undo the multiplication.

3x ÷ 3 = 15 ÷ 3 → x = 5

Check by plugging x = 5 back in.

3(5) + 7 = 15 + 7 = 22 ✓

✓

The answer is x = 5. The equation is balanced.

Now you try

Use the same two moves: undo addition or subtraction first, then undo multiplication or division. Grab a piece of paper.

Solve for x:

5x − 9 = 16

Show the solution

Add 9 to both sides to undo the −9.

5x − 9 + 9 = 16 + 9 → 5x = 25

Divide both sides by 5 to undo the multiplication.

5x ÷ 5 = 25 ÷ 5 → x = 5

Check by substituting x = 5.

5(5) − 9 = 25 − 9 = 16 ✓

✓

The answer is x = 5. Nice work.

That's a Numberbender lesson.

If that felt clear and human — that's the whole idea. Keep going with full courses in algebra, statistics, and beyond.

Browse all courses → Find the right course for me