Advanced MathMediumGrowth factor over a fixed step in an exponential function
Advanced Math practice question
The function f is defined by f(x) = 5 · 3^x. For any value of x, f(x + 2) is how many times f(x)?
Answer: 9
f(x + 2) = 5 · 3^(x+2) = 5 · 3^x · 3² = 9 · f(x). Each step multiplies by 3, so two steps multiply by 9.
Common wrong answers
- If you answered 3
- 3 is the factor for one step, not two.
- If you answered 6
- 6 adds the factor 3 twice instead of multiplying it twice.
- If you answered 45
- 45 is 5 × 9, but the 5 is already part of f(x).
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