Posted by alyssa on Thursday, May 19, 2011 at 10:20am.
I don't understand how to do this problem. Please help!
Find an exponential function of the form f(x) = bax that has a yintercept of 2 and passes through the point (2, 98). For example, if the equation is f(x) = 2(7)x respond by entering the answer as 2(7)^x

algebra  Reiny, Thursday, May 19, 2011 at 10:38am
I think you meant:
y = b(a^x)
you have 2 points, (0,2) and (2,98) which lie on this graph
sub in (0,2)
2 = b(a^0) > b = 2
so y = 2(a^x), now sub in (2,98)
98 = 2(a^2)
49 = a^2
a = ± 7
so your equation is y = 2(7)^x
(strange that they would give you the actual answer as a hint or example)