Expand Binomial Product
1. **State the problem:** Simplify the expression $$(3-x)^2 (4+x)^2$$.
2. **Rewrite the expression:** Notice this is a product of two squared binomials:
$$((3-x)(4+x))^2$$
3. **Expand the inner product:** Use FOIL:
$$(3-x)(4+x) = 3 \times 4 + 3 \times x - x \times 4 - x \times x = 12 + 3x - 4x - x^2$$
4. **Simplify inside:**
$$12 + 3x - 4x - x^2 = 12 - x - x^2$$
5. **Rearrange into standard polynomial form:**
$$-x^2 - x + 12$$
6. **Square the result:**
$$(-(x^2 + x - 12))^2 = (x^2 + x - 12)^2$$
7. **Expand the square:** Use the formula $$(a+b+c)^2 = a^2 + 2ab + 2ac + b^2 + 2bc + c^2$$ where $a = x^2$, $b = x$, $c = -12$:
$$ (x^2)^2 + 2 \times x^2 \times x + 2 \times x^2 \times (-12) + x^2 + 2 \times x \times (-12) + (-12)^2$$
Compute each term:
$$ x^4 + 2x^3 - 24x^2 + x^2 -24x + 144$$
8. **Combine like terms:**
$$x^4 + 2x^3 - 23x^2 - 24x + 144$$
**Final answer:**
$$ (3 - x)^2 (4 + x)^2 = x^4 + 2x^3 - 23x^2 - 24x + 144 $$