Write the exponential function that passes through the points (3, 10) and (5, 40)

  y = (5/4)2^x

Step-by-step explanation:

The function value increases by a factor of 40/10 = 4 when x increases by 2. The function can be written as ...

  y = (reference value)·(growth factor)^((x -reference)/(change in x for growth factor))

  y = 10·4^((x-3)/2) . . . . . . using point (3, 10) as a reference

This can be simplified to ...

  y = 10·2^(x -3) = 10/8·2^x

  y = (5/4)2^x

22 dimes and 9 nickels

step-by-step explanation: