Math Problem Statement

. Diketahui f(x) = x + 5, g(x) = 4x - 3, dan h(x) = 2x + 1. Pernya

A. (f^ -1 g^ -1 h^ -1 ) (x) = (x + 45)/8

B. (f^ -1 h^ -1 g^ -1 ) (x) = (x - 41)/8

C. (g^ -1 f^ -1 h^ -1 ) (x) = (x - 5)/8

D. (g¯¹¹¹)(x) = x-12 8

E. (h¯¹g¯¹ of¹)(x) = x -1 6 8

Solution

To solve this problem, we need to break it down step by step by focusing on the operations related to the composition of inverse functions.

We are given the following functions:

  • f(x)=x+5f(x) = x + 5
  • g(x)=4x3g(x) = 4x - 3
  • h(x)=2x+1h(x) = 2x + 1

Step 1: Find the inverse of each function

To find the inverse of a function, we reverse the operations in the original function. This means solving for xx in terms of yy when y=f(x),g(x),h(x)y = f(x), g(x), h(x).

Inverse of f(x)=x+5f(x) = x + 5:

Let y=f(x)y = f(x). This gives us: y=x+5y = x + 5 Solving for xx: x=y5x = y - 5 Thus, f1(x)=x5f^{-1}(x) = x - 5.

Inverse of g(x)=4x3g(x) = 4x - 3:

Let y=g(x)y = g(x). This gives us: y=4x3y = 4x - 3 Solving for xx: x=y+34x = \frac{y + 3}{4} Thus, g1(x)=x+34g^{-1}(x) = \frac{x + 3}{4}.

Inverse of h(x)=2x+1h(x) = 2x + 1:

Let y=h(x)y = h(x). This gives us: y=2x+1y = 2x + 1 Solving for xx: x=y12x = \frac{y - 1}{2} Thus, h1(x)=x12h^{-1}(x) = \frac{x - 1}{2}.


Step 2: Verify the given options

Now we will check the composition of inverse functions as described in the options.

A. (f1g1h1)(x)=x+458(f^{-1} \circ g^{-1} \circ h^{-1})(x) = \frac{x + 45}{8}

We need to compute f1(g1(h1(x)))f^{-1}(g^{-1}(h^{-1}(x))):

  1. Start with h1(x)=x12h^{-1}(x) = \frac{x - 1}{2}.
  2. Next, apply g1g^{-1} to this: g1(h1(x))=g1(x12)=x12+34=x+58g^{-1}(h^{-1}(x)) = g^{-1}\left( \frac{x - 1}{2} \right) = \frac{\frac{x - 1}{2} + 3}{4} = \frac{x + 5}{8}
  3. Finally, apply f1f^{-1} to the result: f1(x+58)=x+585=x+5408=x358f^{-1}\left( \frac{x + 5}{8} \right) = \frac{x + 5}{8} - 5 = \frac{x + 5 - 40}{8} = \frac{x - 35}{8} Since this doesn't match the given expression x+458\frac{x + 45}{8}, Option A is incorrect.

B. (f1h1g1)(x)=x418(f^{-1} \circ h^{-1} \circ g^{-1})(x) = \frac{x - 41}{8}

We need to compute f1(h1(g1(x)))f^{-1}(h^{-1}(g^{-1}(x))):

  1. Start with g1(x)=x+34g^{-1}(x) = \frac{x + 3}{4}.
  2. Next, apply h1h^{-1} to this: h1(g1(x))=h1(x+34)=x+3412=x18h^{-1}(g^{-1}(x)) = h^{-1}\left( \frac{x + 3}{4} \right) = \frac{\frac{x + 3}{4} - 1}{2} = \frac{x - 1}{8}
  3. Finally, apply f1f^{-1} to the result: f1(x18)=x185=x1408=x418f^{-1}\left( \frac{x - 1}{8} \right) = \frac{x - 1}{8} - 5 = \frac{x - 1 - 40}{8} = \frac{x - 41}{8} This matches the given expression, so Option B is correct.

C. ( (g^{-1} \circ f^{-1} \circ h

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Math Problem Analysis

Mathematical Concepts

Algebra
Inverse Functions
Function Composition

Formulas

Inverse of f(x) = x + 5 is f^{-1}(x) = x - 5
Inverse of g(x) = 4x - 3 is g^{-1}(x) = (x + 3) / 4
Inverse of h(x) = 2x + 1 is h^{-1}(x) = (x - 1) / 2

Theorems

Inverse Function Theorem
Function Composition

Suitable Grade Level

Grades 10-12