Write an equation that models the sequence 400, 200, 100, 50,
a) y = 400(2^x)
b) y = 50 (2^x)
c) y = 1/2x + 400
d) y = 400(1/2)^x-1

hello from mrbilldoesmath!

answer:   x^2 + y^2 = 1024

discussion:

the equation of a circle with center (h,k) and radius "r" is

(x-h)^2 + (y-k)^2 = r^2.

in our case

(x-0)^2 + (y-0) ^2 = 32^2 = 1024

you,

mrb

the correct answer is c