algebra I

Solving the equation by isolating the variable


Let’s say you have an equation like 2y + 7 = 17 and want to know (as in, your teacher or homework asks) what value of y makes the equation true. To answer the question, you want to transform the equation to an equivalent equation with y alone by itself on one side and a constant on the other. You need to isolate y.

To do so, you need to apply both the addition and multiplication properties of equality.


You can solve the equation in another order: Divide both sides by 2 first, and then subtract. We solve the same equation using this process. Note a crucial point: Every term in the equation must be divided by 2, including the 7 on the left side of the equation.


Now, it’s your turn. The calculator below lets you add, subtract, multiply or divide both sides of an equation by any number you like.


Use the calculator to solve the equation. First, press the keys for add, subtract, multiply or divide. Then press the number and then press the = key.