Question

Which exponential function goes through the points (1, 32) and (4, 2048)?

f(x) = 4(4)x

f(x) = 8(2)-x

f(x) = 8(4)x

f(x) = 4(4)-x

Answer 1

none of those appear to be exponential functions ....

Answer 2

f(x) = 4(4)^x

f(x) = 8(2)^-x

f(x) = 8(4)^x

f(x) = 4(4)^-x

Answer 3

better :) now tell me, what do we know about a negative exponent, do they get bigger in value or smaller in value for x>1?

Answer 4

Smaller?

Answer 5

smaller is correct, even tho i worded the question almost badly; the options given would get smaller for negative exponents ... since the value at x=4 is bigger than at x=1, we can rule out 2 options, now test the other 2 for when x=1

Answer 6

It's not the last one either right?

Answer 7

Is it A?

Answer 8

yeah, 2nd and 4th ones are just plan off

when x=1, the other 2 options are simple enough to determine

Answer 9

4(4)^1 = 16, not 32 ... so lets avoid A

Answer 10

So C would be the best option?
I'm really bad at Math.

Answer 11

:) C is what I would pick yes: 8(4)^1 = 32 ... and we want (1,32) so it fits the best

Answer 12

thanks!

Answer 13

yw