Advanced MathMediumComposition of a quadratic and a square-root function
Advanced Math practice question
The functions f and g are defined by f(x) = x² − 4 and g(x) = √(x + 4). What is the value of g(f(3))?
Answer: 3
f(3) = 9 − 4 = 5. Then g(5) = √(5 + 4) = √9 = 3.
Common wrong answers
- If you answered 5
- 5 is f(3), the inner value only.
- If you answered 9
- 9 is 5 + 4, before taking the square root.
- If you answered -1
- −1 comes from √(5 − 4), subtracting inside the root instead of adding.
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