Factor -4x(x+3)+3x^2(x+3)

$- 4 x (x + 3) + 3 x^{2} (x + 3)$

Factor $- x (x + 3)$ out of $- 4 x (x + 3) + 3 x^{2} (x + 3)$ .

Reorder $- 4 x (x + 3)$ and $3 x^{2} (x + 3)$ .

$3 x^{2} (x + 3) - 4 x (x + 3)$

Factor $- x (x + 3)$ out of $3 x^{2} (x + 3)$ .

$- x (x + 3) (- 3 x) - 4 x (x + 3)$

Factor $- x (x + 3)$ out of $- 4 x (x + 3)$ .

$- x (x + 3) (- 3 x) - x (x + 3) (4)$

Factor $- x (x + 3)$ out of $- x (x + 3) (- 3 x) - x (x + 3) (4)$ .

$- x (x + 3) (- 3 x + 4)$

Factor.

Factor $- 1$ out of $- 3 x + 4$ .

Factor $- 1$ out of $- 3 x$ .

$- x (x + 3) (- (3 x) + 4)$

Rewrite $4$ as $- 1 (- 4)$ .

$- x (x + 3) (- (3 x) - 1 (- 4))$

Factor $- 1$ out of $- (3 x) - 1 (- 4)$ .

$- x (x + 3) (- (3 x - 4))$

Remove unnecessary parentheses.

$- x (x + 3) \cdot - 1 (3 x - 4)$

Combine exponents.

Factor out negative.

$- ((x (x + 3)) \cdot - 1 (3 x - 4))$

Multiply $- 1$ by $- 1$ .

$1 ((x (x + 3)) (3 x - 4))$

Multiply $x$ by $1$ .

$x ((x + 3) (3 x - 4))$

Remove unnecessary parentheses.

$x (x + 3) (3 x - 4)$