## Precalculus: Mathematics for Calculus, 7th Edition

First, simplify the equation 1.$4x+7=9x-3$ 2. Add 3 to both sides:$4x+10=9x$ 3. Subtract 4x from both sides: $10=5x$ a. Plug in -2 to see if it makes the equation true: 1. $10=5\times-2$ 2. $10=-10$ The equation is not true, so -2 is not a solution of the equation. b. Plug in 2 to see if it makes the equation true: 1. $10=5\times2$ 2. $10=10$ The equation is true, so 2 is a solution of the equation.