1. **State the problem:**
Find the product of the functions $f(x) = 4 - x^2$ and $g(x) = 2 - x$, i.e., find $(fg)(x) = f(x) \cdot g(x)$.
2. **Formula and rules:**
The product of two functions is given by:
$$ (fg)(x) = f(x) \times g(x) $$
We multiply the expressions for $f(x)$ and $g(x)$ and simplify.
3. **Intermediate work:**
$$ (fg)(x) = (4 - x^2)(2 - x) $$
Use distributive property:
$$ = 4 \times 2 - 4 \times x - x^2 \times 2 + x^2 \times x $$
$$ = 8 - 4x - 2x^2 + x^3 $$
Rearranged in standard polynomial form:
$$ (fg)(x) = x^3 - 2x^2 - 4x + 8 $$
4. **Answer:**
The correct choice is (b) $x^3 - 2x^2 - 4x + 8$.
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5. **Next problem:**
Given $f(x) = 2x^2 + x - 3$ and $g(x) = x - 1$, express
$$ f(x) \cdot g(x) - [f(x) + g(x)] $$
in standard form.
6. **Formula and rules:**
First find $f(x) \cdot g(x)$, then subtract $f(x) + g(x)$.
7. **Intermediate work:**
Calculate $f(x) \cdot g(x)$:
$$ (2x^2 + x - 3)(x - 1) = 2x^2 \times x + 2x^2 \times (-1) + x \times x + x \times (-1) - 3 \times x - 3 \times (-1) $$
$$ = 2x^3 - 2x^2 + x^2 - x - 3x + 3 $$
Simplify:
$$ = 2x^3 - 2x^2 + x^2 - x - 3x + 3 = 2x^3 - x^2 - 4x + 3 $$
Calculate $f(x) + g(x)$:
$$ (2x^2 + x - 3) + (x - 1) = 2x^2 + x + x - 3 - 1 = 2x^2 + 2x - 4 $$
Subtract:
$$ f(x) \cdot g(x) - [f(x) + g(x)] = (2x^3 - x^2 - 4x + 3) - (2x^2 + 2x - 4) $$
Distribute minus:
$$ = 2x^3 - x^2 - 4x + 3 - 2x^2 - 2x + 4 $$
Combine like terms:
$$ = 2x^3 - (x^2 + 2x^2) - (4x + 2x) + (3 + 4) $$
$$ = 2x^3 - 3x^2 - 6x + 7 $$
8. **Final answer:**
$$ 2x^3 - 3x^2 - 6x + 7 $$
Function Products 7F914B
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