Simplify -3(x^2+x-1)+12

$- 3 (x^{2} + x - 1) + 12$

Simplify each term.

Apply the distributive property.

$- 3 x^{2} - 3 x - 3 \cdot - 1 + 12$

Multiply $- 3$ by $- 1$ .

$- 3 x^{2} - 3 x + 3 + 12$

Add $3$ and $12$ .

$- 3 x^{2} - 3 x + 15$