Question

I dont know which graph it is please help

Answer 1

One simple approach would be to choose an x value, such as x = 8, calculate y using the given formula, and then choosing the graph that shows a C(t) value closer to your calculated value.

Please evaluate C(8).

Answer 2

Let's plug in a couple of a values for t and match them up against the graphs.

$C(t) = 50000 (0.9)^t - 2000$

$C(0) = 50000-2000=48000$

$C(1) = 50000(.9)-2000 = 43000$

$C(2) = 50000(.9)^2-2000=50000(.81) -2000 = 38500$

$C(8) = 50000(.9)^8-2000 \approx 19523$

$C(20) = 50000(.9)^8-2000 \approx 4079$

Look for

(0,48000), (1,43000), (2,38500),(8,19523),(20,4079)

A. C(8) is way off

B C(0) isn't exactly 48000 like A and C

C. C(0) matches, C(8) matches, C(20) matches, SELECT CHOICE C

D. C(0) and C(20) are off.

Choice C