Advanced MathHardBase of an exponential function from two points
Advanced Math practice question
The graph of f(x) = a·bˣ, where a and b are positive constants, passes through the points (0, 5) and (2, 45). What is the value of b?
Answer: 3
f(0) = a = 5, and f(2) = 5b² = 45 gives b² = 9, so b = 3.
Common wrong answers
- If you answered 5
- 5 is a.
- If you answered 9
- 9 is b², not b.
- If you answered 40
- 40 is the difference of the y-values.
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