Things You'll Need

Instructions

How to Solve Math Problems With a Variable

1

Copy the equation exactly as it appears in the book onto your paper. For this example, use 3x + 5 = 39 + 2.
2

Simplify anything that can be simplified. In this equation, 39 + 2 should be added together. This gives you 3x + 5 = 41.
3

Identify the terms. Terms are the letter and number combinations that are separated by addition, subtraction or equal signs. In this example, the terms are 3x, 5 and 41.
4

Isolate the term that contains the variable. To eliminate the 5, you have to do the opposite operation than the one that is being done in the equation. In 3x + 5 = 41, the 5 is being added, so you need to subtract it (3x +5 - 5 = 41).
5

Subtract 5 from the other side of the equal sign in order to keep the equation balanced (3x + 5 - 5 = 41 - 5). This yields 3x + 0 = 36, or simply 3x = 36.
6

Isolate the variable itself. The 3 is being multiplied with x, so to eliminate the 3 you must divide that side of the equation by 3. This must also be repeated on the opposite side of the equal sign (3x/3 = 36/3).
7

Solve the equation. By dividing the 3 by 3, you get 1. Multiplying 1 by x yields x. Dividing 36 by 3 gives you 12. The answer to the equation is x = 12.
8

Check the equation by putting the 12 in for the variable (3 12 + 5 = 41). If you have solved the equation correctly, the equation will be balanced. Since 3 12 + 5 does, in fact, equal 41, you are done.