How do you find the answer to an expression with a variable?

Answer 1

Assuming you meant "equation" (an equation is one or more terms on each side of an equals sign that have the same value, such as x+7=12), you have to get the variable alone on one side, by "undoing" things until it is alone. Remember, what you do to one side of an equation, you must do to the other side. So:

x+7=12

-7 -7

x=5

Since 12 was 7 more than X, you subtract 7 from both sides, negating the 7 on the left, and leaving you with x=5.