Math topics

Basic algebra

In a one-step equation, use the inverse operation on both sides to isolate x. Addition undoes subtraction; multiplication undoes division. Whatever you do to one side, do to the other so equality stays true.

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Worked example

Problem. Solve for x: x − 7 = −5

1. Add 7 to both sides to undo subtracting 7.
2. x − 7 + 7 = −5 + 7.
3. x = 2. Check: 2 − 7 = −5.

Answer. 2

Practice set

1. Practice 1. Solve: x + 4 = 10

   Show answer

   6

2. Practice 2. Solve: x − 3 = 5

   Show answer

   8

3. Practice 3. Solve: 2x = 14

   Show answer

   7

Related pages

• One- and two-step equations
• expressions
• Order of operations

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