### Home > CCA2 > Chapter 2 > Lesson 2.1.5 > Problem 2-72

2-72.

Find the equation of an exponential function that passes through each pair of points. 2-72a HW eTool (Desmos) and 2-72b HW eTool (Desmos). Homework Help ✎.

(2, 9) and (4, 324)

Use the eTool below to help you solve part (a).

Click the link at right for the full version of the eTool: CCA2 2-72a HW eToolUse the equation

to help you here. Begin by substituting one of the points for*x*and*y*.Next, substitute the other ordered pair for

*x*and*y*.Use substitution, and solve for

*b*.Now, solve for

*a*.(−1, 40) and (0, 12)

Use the eTool below to help you solve part (b).

Click the link at right for the full version of the eTool: CCA2 2-72b HW eToolLook at the hints in part (a).