Math Problem Statement

Consider the functions f(x)=2x2−3 and g(x)=−x+6.

f(g(4))=

g(f(4))=

Solution

Let's solve both of these expressions step by step.

1. Finding f(g(4))f(g(4)):

  • First, we need to find g(4)g(4): g(x)=x+6g(x) = -x + 6 Substitute x=4x = 4 into g(x)g(x): g(4)=(4)+6=4+6=2g(4) = -(4) + 6 = -4 + 6 = 2
  • Now, we use this result to find f(g(4))=f(2)f(g(4)) = f(2): f(x)=2x23f(x) = 2x^2 - 3 Substitute x=2x = 2 into f(x)f(x): f(2)=2(2)23=2(4)3=83=5f(2) = 2(2)^2 - 3 = 2(4) - 3 = 8 - 3 = 5 Thus, f(g(4))=5f(g(4)) = 5.

2. Finding g(f(4))g(f(4)):

  • First, we need to find f(4)f(4): f(x)=2x23f(x) = 2x^2 - 3 Substitute x=4x = 4 into f(x)f(x): f(4)=2(4)23=2(16)3=323=29f(4) = 2(4)^2 - 3 = 2(16) - 3 = 32 - 3 = 29
  • Now, we use this result to find g(f(4))=g(29)g(f(4)) = g(29): g(x)=x+6g(x) = -x + 6 Substitute x=29x = 29 into g(x)g(x): g(29)=(29)+6=29+6=23g(29) = -(29) + 6 = -29 + 6 = -23 Thus, g(f(4))=23g(f(4)) = -23.

Final Answers:

  • f(g(4))=5f(g(4)) = 5
  • g(f(4))=23g(f(4)) = -23

Do you want more details or have any questions?


Here are 5 related questions:

  1. What is the general form of f(g(x))f(g(x)) for these functions?
  2. How would f(g(x))f(g(x)) change if g(x)=2x+5g(x) = -2x + 5?
  3. What is f(f(4))f(f(4))?
  4. How would the results change if f(x)=x23xf(x) = x^2 - 3x?
  5. Can we solve for g(g(4))g(g(4))?

Tip: Always solve functions step by step, ensuring substitution is done accurately for nested functions.

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Math Problem Analysis

Mathematical Concepts

Algebra
Function Composition
Quadratic Functions
Linear Functions

Formulas

f(x) = 2x^2 - 3
g(x) = -x + 6
Function Composition: f(g(x)) and g(f(x))

Theorems

Substitution Method for Function Composition

Suitable Grade Level

Grades 9-11