How do you find the formula of an exponential graph given A = (1, 12) and B = (2, 48)?

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Answer 1 · 2015-10-30T18:37:25

This graph has a formula: #y=3*(4^x)#

We are looking for a function #y=a*b^x# which passes through #(1,12)# and #(2,24)#

If we substitute the points' coordinates to the function formula we get:

#{(a*b=12),(a*b^2=48):}#

If we substitute first equation to the second we get: #12*b=48#

so #b=4#

Now if we substitute #b=4# into first equation we get: #4a=12#

#a=3#

Finally we can writhe the answer: The function is: #y=3*4^x#