Simplify Polynomial Expression
1. Start by stating the problem: Simplify and expand the expression $$-2x^2 + 9x - 4 - (-2 - x)(3x - 12)$$.
2. Expand the product $$(-2 - x)(3x - 12)$$ using the distributive property:
$$-2 \times 3x = -6x$$
$$-2 \times (-12) = +24$$
$$-x \times 3x = -3x^2$$
$$-x \times (-12) = +12x$$
3. Combine these to get:
$$-6x + 24 - 3x^2 + 12x$$
4. Now, substitute back into the original expression, remembering the minus in front:
$$-2x^2 + 9x - 4 - ( -6x + 24 - 3x^2 + 12x )$$
5. Distribute the minus sign over the parentheses:
$$-2x^2 + 9x - 4 + 6x - 24 + 3x^2 - 12x$$
6. Combine like terms:
For $$x^2$$ terms: $$-2x^2 + 3x^2 = x^2$$
For $$x$$ terms: $$9x + 6x - 12x = 3x$$
Constants: $$-4 - 24 = -28$$
7. The simplified expression is:
$$x^2 + 3x - 28$$
Final answer: $$\boxed{x^2 + 3x - 28}$$