Chapter 1 - Foundations for Algebra - 1-8 An Introduction to Equations - Practice and Problem-Solving Exercises - Page 57: 40

-2

In order to solve this algebraic expression, we must isolate the variable. A variable is a letter in the problem (for instance, in the equation 5x=10, x is the variable). Because multiplication and division are inverse operations (they cancel each other out), we know we must divide when a number is being multiplied by the variable and multiply when the variable is being divided by a number.In the equation -4=2y, we must get rid of the 2, so we divide both sides by two to get: y=-2