exponential function has form y = a(b)^x
we see that when x = 0, then y = 10. Substitute those values to solve for an unknown
10 = a(b)^0
since b^0 is 1 we are left with a = 10.
we have y = 10(b)^x
to find b, use another point on the table. when x = 1, y = 30 so
30 = 10(b)^1
30 = 10b
b = 30/10
b = 3
function: y = 10 · (3)^x
(can also notice that y-values are all being mutliplied by 3)