Write an exponential function in the form y = ab^x that goes through points (0,20) and (8,5120)

9514 1404 393

  y = 20·2^x

Step-by-step explanation:

Use the given points to write two equations, then solve for 'a' and 'b'.

  20 = a·b^0 = a

  5120 = a·b^8 = 20·b^8   ⇒   256 = b^8

  b = 256^(1/8) = 2

Your function is ...

  y = 20·2^x

where are the choices?

x = 3 ± √(5+y)