Colorful House of Math logo
Log in

Checking the Answer


After you’ve solved an equation, you can check the answer by substituting the answer you got for x into the equation. Then, you check to see if you get the same result on both the left-hand and the right-hand side.

Example 1

Check if x = 3 is a solution to x 3 + 1 = 4 2x 3

Substituting x = 3 on the left-hand side gives you

x 3 + 1 = 3 3 + 1 = 1 + 1 = 2

Substituting x = 3 on the right-hand side gives you

4 2x 3 = 4 2 3 3 = 4 6 3 = 4 2 = 2

4 2x 3 = 4 2 3 3 = 4 6 3 = 4 2 = 2

This means that both the left-hand side and right-hand side are equal to 2 when you substitute 3 for x. You’ve now checked the answer, and since both sides are equal, it means that x = 3 is a correct solution.

Note! It is possible for there to be more than one solution for x in many equations, especially those where x is raised to a power.

Want to know more?Sign UpIt's free!
White arrow pointing to the LeftPrevious entry
Activities 6
Next entryWhite arrow pointing to the right
Activities 7