16Hit1600
Advanced MathVery hardY-intercept of an exponential through two points

Advanced Math practice question

In the xy-plane, the graph of an exponential function y = a·bˣ passes through (1, 12) and (2, 48). What is the y-intercept of the graph?

Answer: 3

b = 48/12 = 4, and a·4 = 12 gives a = 3; the y-intercept is a = 3.

Common wrong answers

If you answered 0
An exponential function never reaches 0.
If you answered 4
4 is b.
If you answered 12
12 is the value at x = 1.

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