1. **State the problem:**
We are given two functions:
$$f(x) = 2x + 3$$
and
$$g(x) = -\frac{2}{3}x + 4$$
We need to find:
a) The composition $g \circ f(x)$.
b) The inverse function $g^{-1}(x)$.
c) The value of $m$ such that $f(m) = 2[g \circ f(1)] - \frac{1}{3}$.
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2. **Find $g \circ f(x)$:**
By definition, $g \circ f(x) = g(f(x))$.
Substitute $f(x)$ into $g$:
$$g(f(x)) = -\frac{2}{3}(2x + 3) + 4$$
Distribute:
$$= -\frac{2}{3} \times 2x - \frac{2}{3} \times 3 + 4 = -\frac{4}{3}x - 2 + 4$$
Simplify constants:
$$= -\frac{4}{3}x + 2$$
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3. **Find $g^{-1}(x)$:**
Start with:
$$y = -\frac{2}{3}x + 4$$
Swap $x$ and $y$ to find inverse:
$$x = -\frac{2}{3}y + 4$$
Solve for $y$:
$$x - 4 = -\frac{2}{3}y$$
Multiply both sides by $-\frac{3}{2}$:
$$y = \cancel{-\frac{3}{2}}(x - 4) \times \cancel{-1} = -\frac{3}{2}x + 6$$
So,
$$g^{-1}(x) = -\frac{3}{2}x + 6$$
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4. **Find $m$ such that $f(m) = 2[g \circ f(1)] - \frac{1}{3}$:**
First, find $f(1)$:
$$f(1) = 2(1) + 3 = 5$$
Next, find $g \circ f(1) = g(f(1)) = g(5)$:
$$g(5) = -\frac{2}{3} \times 5 + 4 = -\frac{10}{3} + 4 = -\frac{10}{3} + \frac{12}{3} = \frac{2}{3}$$
Calculate the right side:
$$2 \times \frac{2}{3} - \frac{1}{3} = \frac{4}{3} - \frac{1}{3} = 1$$
So,
$$f(m) = 1$$
Recall $f(m) = 2m + 3$, set equal to 1:
$$2m + 3 = 1$$
Solve for $m$:
$$2m = 1 - 3 = -2$$
$$m = \frac{\cancel{2}m}{\cancel{2}} = \frac{-2}{2} = -1$$
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**Final answers:**
a) $$g \circ f(x) = -\frac{4}{3}x + 2$$
b) $$g^{-1}(x) = -\frac{3}{2}x + 6$$
c) $$m = -1$$
Function Composition 21B6C3
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