Answer
$x=3$
Work Step by Step
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.
$x=3$
