1. We are asked to find the inverse of each given function and then graph both the function and its inverse.
2. To find the inverse of a function $f(x)$, we swap $x$ and $y$ in the equation $y=f(x)$ and then solve for $y$.
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**13) Find the inverse of** $g(x) = \frac{7x + 18}{2}$
Step 1: Write $y = \frac{7x + 18}{2}$.
Step 2: Swap $x$ and $y$: $$x = \frac{7y + 18}{2}$$
Step 3: Multiply both sides by 2: $$2x = 7y + 18$$
Step 4: Isolate $y$: $$7y = 2x - 18$$
Step 5: Divide both sides by 7: $$y = \frac{2x - 18}{7}$$
So, the inverse is $$g^{-1}(x) = \frac{2x - 18}{7}$$.
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**14) Find the inverse of** $f(x) = x + 3$
Step 1: Write $y = x + 3$.
Step 2: Swap $x$ and $y$: $$x = y + 3$$
Step 3: Isolate $y$: $$y = x - 3$$
So, the inverse is $$f^{-1}(x) = x - 3$$.
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**15) Find the inverse of** $f(x) = -x + 3$
Step 1: Write $y = -x + 3$.
Step 2: Swap $x$ and $y$: $$x = -y + 3$$
Step 3: Isolate $y$: $$-y = x - 3$$
Step 4: Multiply both sides by $-1$: $$y = -x + 3$$
So, the inverse is $$f^{-1}(x) = -x + 3$$.
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**16) Find the inverse of** $f(x) = 4x$
Step 1: Write $y = 4x$.
Step 2: Swap $x$ and $y$: $$x = 4y$$
Step 3: Divide both sides by 4: $$y = \frac{x}{4}$$
So, the inverse is $$f^{-1}(x) = \frac{x}{4}$$.
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**17) Find the inverse of** $f(x) = -1 - \frac{1}{5}x$
Step 1: Write $y = -1 - \frac{1}{5}x$.
Step 2: Swap $x$ and $y$: $$x = -1 - \frac{1}{5}y$$
Step 3: Add 1 to both sides: $$x + 1 = -\frac{1}{5}y$$
Step 4: Multiply both sides by $-5$: $$-5(x + 1) = y$$
So, the inverse is $$f^{-1}(x) = -5(x + 1) = -5x - 5$$.
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**18) Find the inverse of** $g(x) = \frac{1}{x - 1}$
Step 1: Write $y = \frac{1}{x - 1}$.
Step 2: Swap $x$ and $y$: $$x = \frac{1}{y - 1}$$
Step 3: Multiply both sides by $y - 1$: $$x(y - 1) = 1$$
Step 4: Distribute $x$: $$xy - x = 1$$
Step 5: Add $x$ to both sides: $$xy = x + 1$$
Step 6: Divide both sides by $x$: $$y = \frac{x + 1}{x}$$
So, the inverse is $$g^{-1}(x) = \frac{x + 1}{x}$$.
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**19) Find the inverse of** $f(x) = -2x^3 + 1$
Step 1: Write $y = -2x^3 + 1$.
Step 2: Swap $x$ and $y$: $$x = -2y^3 + 1$$
Step 3: Subtract 1 from both sides: $$x - 1 = -2y^3$$
Step 4: Divide both sides by $-2$: $$\frac{x - 1}{-2} = y^3$$
Step 5: Take the cube root of both sides: $$y = \sqrt[3]{\frac{x - 1}{-2}} = \sqrt[3]{-\frac{x - 1}{2}}$$
So, the inverse is $$f^{-1}(x) = \sqrt[3]{-\frac{x - 1}{2}}$$.
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**20) Find the inverse of** $g(x) = \frac{-x - 5}{3}$
Step 1: Write $y = \frac{-x - 5}{3}$.
Step 2: Swap $x$ and $y$: $$x = \frac{-y - 5}{3}$$
Step 3: Multiply both sides by 3: $$3x = -y - 5$$
Step 4: Add 5 to both sides: $$3x + 5 = -y$$
Step 5: Multiply both sides by $-1$: $$y = -3x - 5$$
So, the inverse is $$g^{-1}(x) = -3x - 5$$.
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**Summary of inverses:**
- $g^{-1}(x) = \frac{2x - 18}{7}$
- $f^{-1}(x) = x - 3$
- $f^{-1}(x) = -x + 3$
- $f^{-1}(x) = \frac{x}{4}$
- $f^{-1}(x) = -5x - 5$
- $g^{-1}(x) = \frac{x + 1}{x}$
- $f^{-1}(x) = \sqrt[3]{-\frac{x - 1}{2}}$
- $g^{-1}(x) = -3x - 5$
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**Desmos functions for graphing:**
- For each function $f(x)$ and its inverse $f^{-1}(x)$, plot both on the same coordinate grid.
Function Inverses 969Ce5
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