1. **State the problem:** Show that for the functions $f(x) = 7x - 2$ and $g(x) = \frac{1}{7}(x + 2)$, the compositions satisfy $(f \circ g)(x) = (g \circ f)(x) = x$.
2. **Recall the definition of composition:**
- $(f \circ g)(x) = f(g(x))$
- $(g \circ f)(x) = g(f(x))$
3. **Calculate $(f \circ g)(x)$:**
$$
(f \circ g)(x) = f\left(g(x)\right) = f\left(\frac{1}{7}(x + 2)\right) = 7 \cdot \frac{1}{7}(x + 2) - 2
$$
Simplify the multiplication:
$$
7 \cdot \frac{1}{7}(x + 2) = \cancel{7} \cdot \frac{1}{\cancel{7}}(x + 2) = x + 2
$$
So,
$$
(f \circ g)(x) = x + 2 - 2 = x
$$
4. **Calculate $(g \circ f)(x)$:**
$$
(g \circ f)(x) = g\left(f(x)\right) = g(7x - 2) = \frac{1}{7}((7x - 2) + 2)
$$
Simplify inside the parentheses:
$$
(7x - 2) + 2 = 7x
$$
So,
$$
(g \circ f)(x) = \frac{1}{7} \cdot 7x = \cancel{\frac{1}{7}} \cdot \cancel{7} x = x
$$
5. **Conclusion:** Both compositions return $x$, so $(f \circ g)(x) = (g \circ f)(x) = x$.
This shows that $f$ and $g$ are inverse functions of each other.
Composition Inverse 8Ed033
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