## Intermediate Algebra (6th Edition)

$x=3$
We are given the equation $3x(x+5)-12=3x^{2}+10x+3$. We can solve for x by first using the distributive property to simplify the left side. $3x(x+5)-12=3x^{2}+15x-12=3x^{2}+10x+3$ Subtract $3x^{2}$ from both sides. $15x-12=10x+3$ Subtract 10x from both sides. $5x-12=3$ Add 12 to both sides. $5x=15$ Divide both sides by 5. $x=3$