Math Problem Statement

Find the inverse functions of the given functions: 1) g(x) = (x - 5)/(x + 4) 2) f(x) = 4(x - 5) + 3 3) f(x) = 6√(x - 9) 4) h(x) = (2x - 9)/x 5) m(x) = (x - 5)/(x + 1)

Solution

The assignment asks for the inverse functions of the given functions. Let’s work through each one of them:

1. g(x)=x5x+4g(x) = \frac{x - 5}{x + 4}

To find the inverse, follow these steps:

  1. Replace g(x)g(x) with yy:
    y=x5x+4y = \frac{x - 5}{x + 4}
  2. Swap xx and yy:
    x=y5y+4x = \frac{y - 5}{y + 4}
  3. Solve for yy:
    Multiply both sides by y+4y + 4:
    x(y+4)=y5x(y + 4) = y - 5
    xy+4x=y5xy + 4x = y - 5
    Get all terms involving yy on one side:
    xyy=4x5xy - y = -4x - 5
    Factor out yy:
    y(x1)=4x5y(x - 1) = -4x - 5
    Finally, solve for yy:
    y=4x5x1y = \frac{-4x - 5}{x - 1}

So the inverse is: g1(x)=4x5x1g^{-1}(x) = \frac{-4x - 5}{x - 1}


2. f(x)=4(x5)+3f(x) = 4(x - 5) + 3

  1. Replace f(x)f(x) with yy:
    y=4(x5)+3y = 4(x - 5) + 3
  2. Swap xx and yy:
    x=4(y5)+3x = 4(y - 5) + 3
  3. Solve for yy:
    x=4y20+3x = 4y - 20 + 3
    x=4y17x = 4y - 17
    Add 17 to both sides:
    x+17=4yx + 17 = 4y
    Divide by 4:
    y=x+174y = \frac{x + 17}{4}

So the inverse is: f1(x)=x+174f^{-1}(x) = \frac{x + 17}{4}


3. f(x)=6x9f(x) = 6 \sqrt{x - 9}

  1. Replace f(x)f(x) with yy:
    y=6x9y = 6 \sqrt{x - 9}
  2. Swap xx and yy:
    x=6y9x = 6 \sqrt{y - 9}
  3. Solve for yy:
    Divide both sides by 6:
    x6=y9\frac{x}{6} = \sqrt{y - 9}
    Square both sides:
    (x6)2=y9\left( \frac{x}{6} \right)^2 = y - 9
    x236=y9\frac{x^2}{36} = y - 9
    Add 9 to both sides:
    y=x236+9y = \frac{x^2}{36} + 9

So the inverse is: f1(x)=x236+9f^{-1}(x) = \frac{x^2}{36} + 9


4. h(x)=2x9xh(x) = \frac{2x - 9}{x}

  1. Replace h(x)h(x) with yy:
    y=2x9xy = \frac{2x - 9}{x}
  2. Swap xx and yy:
    x=2y9yx = \frac{2y - 9}{y}
  3. Solve for yy:
    Multiply both sides by yy:
    xy=2y9x y = 2y - 9
    Rearrange:
    xy2y=9x y - 2y = -9
    Factor out yy:
    y(x2)=9y(x - 2) = -9
    Divide by (x2)(x - 2):
    y=9x2y = \frac{-9}{x - 2}

So the inverse is: h1(x)=9x2h^{-1}(x) = \frac{-9}{x - 2}


5. m(x)=x5x+1m(x) = \frac{x - 5}{x + 1}

  1. Replace m(x)m(x) with yy:
    y=x5x+1y = \frac{x - 5}{x + 1}
  2. Swap xx and yy:
    x=y5y+1x = \frac{y - 5}{y + 1}
  3. Solve for yy:
    Multiply both sides by y+1y + 1:
    x(y+1)=y5x(y + 1) = y - 5
    xy+x=y5xy + x = y - 5
    Get all terms involving yy on one side:
    xyy=x5xy - y = -x - 5
    Factor out yy:
    y(x1)=x5y(x - 1) = -x - 5
    Finally, solve for yy:
    y=x5x1y = \frac{-x - 5}{x - 1}

So the inverse is: m1(x)=x5x1m^{-1}(x) = \frac{-x - 5}{x - 1}


Would you like any further details or have any questions?

Here are 5 follow-up questions you might explore:

  1. How can you verify that the inverse function you found is correct?
  2. What are the domain and range restrictions of each inverse function?
  3. Why do some inverse functions have restrictions on the domain that the original function did not?
  4. How does the process of finding an inverse change for functions involving square roots?
  5. Can every function have an inverse?

Tip: Always check if the function is one-to-one (i.e., passes the horizontal line test) before attempting to find the inverse.

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Math Problem Analysis

Mathematical Concepts

Inverse Functions
Algebraic Manipulation
Solving Equations

Formulas

y = (x - 5) / (x + 4)
y = 4(x - 5) + 3
y = 6√(x - 9)
y = (2x - 9)/x
y = (x - 5)/(x + 1)

Theorems

Inverse Function Theorem

Suitable Grade Level

Grade 11-12