Chapter 4 - An Introduction to Functions - 4-4 Graphing a Function Rule - Mixed Review - Page 259: 53

y=4 or y=-4

First , we divide both sides of the equation by -2 and later we get the equation /5y/=20 . Based on the property of both negative and positive value can get positive absolute value , we can get two conditions of the equation : 5y=20 or 5y=-20 and divide both sides of the equations by 5 , we could get the answer which y= -4 or y=4