Question

Difficulty: MediumFunctions and Custom Symbol Operations

For all real numbers xx, the function ff is defined by f(x)=3x2f(x) = 3 - x^2. For all real numbers x2x \neq -2, the function gg is defined by g(x)=2x1x+2g(x) = \frac{2x - 1}{x + 2}. What is the value of g(f(3))g(f(-3))?

  1. 134\frac{13}{4}Answer
  2. B
    2314\frac{23}{14}
  3. C
    46-46
  4. D
    42-42
  5. E
    12-\frac{1}{2}

Answer

The correct answer is 134\frac{13}{4}.
First, evaluate the inner expression f(3)=3(3)2=39=6f(-3) = 3 - (-3)^2 = 3 - 9 = -6. Next, evaluate the outer expression at this value: g(6)=2(6)16+2=134=134g(-6) = \frac{2(-6) - 1}{-6 + 2} = \frac{-13}{-4} = \frac{13}{4}.

Step-by-Step Solution

1
Evaluate the inner function f(3)f(-3)
f(3)=3(3)2=39=6f(-3) = 3 - (-3)^2 = 3 - 9 = -6
Applying the definition of f(x)f(x) where the negative base is squared to yield positive 99.
2
Substitute the result into the outer function g(x)g(x)
g(6)=2(6)16+2=1214=134=134g(-6) = \frac{2(-6) - 1}{-6 + 2} = \frac{-12 - 1}{-4} = \frac{-13}{-4} = \frac{13}{4}
Evaluating g(x)g(x) at x=6x = -6 and simplifying the fraction.

Key Concept

Nested Function Evaluation g(f(x))g(f(x))
Estimated Time:1m 30s
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