Write an equation that models the sequence 200 , 500 , 1250

c) y = 80 (2.5)^x

Explanation:

The first term is 80 and the common ratio is 2.5 because every term is being multiplied by 2.5. To figure this out when it is not

obvious, divide the 2nd term by the first term. The equation is y = 80(2.5)^x

We can check the answers by putting the values in the formula

y = 80(2.5)^1

  = 200

y = 80(2.5)^2

  = 80 x 6.25

  = 500

y = 80(2.5)^3

  = 80 x 15.625

  = 1250

y = 80(2.5)^4

  = 80 x 39.0625

  = 3125