How do you find the equation of the exponential function y=a(b)^x which goes through the points(2, 18) and (6,91.125). What is the intercepts of this function?

1 Answer
Feb 20, 2017

y=8(5/4)^x
intercept: (0;8)

Explanation:

It's
a*b^2=18 and a* b^6=91.125 and b>0

then

a=18/b^2 and 18/b^2*b^6=91.125

a=18/b^2 and 18*b^4=91.125

a=18/b^2 and b^4=91.125/18=5.0625

a=18/b^2 and b^2=2.25

a=18/2.25 and b=1.25

a=8 and b=5/4

Then y=8(5/4)^x

If x=0, then y=8*(5/4)^0=8*1=8

It's the one intercept of the function since y=0 AAx
graph{8*(5/4)^x [-10, 5, -1, 15]}