Chapter 9 - Quadratic Functions and Equations - 9-4 Factoring to Solve Quadratic Equations - Practice and Problem-Solving Exercises - Page 558: 32

$5n^2+16n+12 = 0$ $n = -1.2, -2$

$7n^2+16n+15=2n^2+3$ $7n^2+16n+15-2n^2-3=2n^2+3-2n^2-3$ $5n^2+16n+12 = 0$ $5n^2+10n+6n+12 = 0$ $5n(n+2)+6(n+2)=0$ $(5n+6)(n+2)=0$ $5n+6=0$ $5n+6-6 = 0-6$ $5n = -6$ $5n/5=-6/5$ $n = -1.2$ $n+2=0$ $n+2-2=0-2$ $n = -2$