## Intermediate Algebra (6th Edition)

The solution set is $\left\{-11, 6\right\}$.
Multiply the left side: $x^2+5x=66$ Subtract 66 to both sides: $x^2 + 5x - 66 = 66-0 \\x^2+5x-66=0$ Factor the trinomial by looking for factors of $-66$ whose sum is equal to 5. These factors are 11 and $-6$. $(x+11)(x-6)=0$ Equate each factor to zero, then solve each equation. $x+11=0 \text{ o } x-6=0 \\x=-11 \text{ or }x=6$