# algebra

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How do you do this:

Write an exponential function of the form y=ab^x that has a graph through (-2, 25) and (1, 10).

This is what I have so far:
10=ab^1
10/b=a
y=10/b*b^x
2/25=10b^-3
.008=b^-3

Then I am stuck. Am I doing it right so far? How do I continue? Thanks!

25 = (10/b)b^-2
2.5 = b^-3
0.4 = b^3
b=cuberoot(.4)=.7368...
then a=10/.7368... = 13.572..

so y = 13.572(.7368)^x

I checked both data values, they work

gotcha thanks

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