You may want to review multiplying, adding and subtracting fractions first.

An equation is a sentence that says that two expressions are equal to each other. If the expressions just have numbers in them, then the sentence is either true or false. For example, the equation 2 + 2 = 4 is true. If the expressions have x in them, then you need to know what x is to figure out whether the sentence is true or false. A value of x that makes an equation true is called a solution of the equation.

For example, suppose you are given the equation 2(−x) = −1. Then −1 is not a solution, since 2(−(−1)) is 2 times 1, which is 2, and that's not the same as −1. However, 1 ⁄ 2 is a solution, since 2(−1 ⁄ 2) is −1.

If the equation doesn't have x in it at all, then it doesn't matter what x is. So 3 is a solution of 2 + 2 = 4, and so is 1 ⁄ 2, and so is −187235, and so is any other number, because 2 + 2 = 4 no matter what x is. On the other hand, none of these are solutions of 2 + 2 = 5 (since that's false no matter what x is).