Respuesta :
f(d) = 72 - 3d
if d = 3
f(d) = 72 -3d = 72 - 3(3) = 72 - 9 = 63 inches
if d = 5
f(d) = 72 -3d = 72 - 3(5) = 72 - 15 = 57 inches
so
if d = 17
f(d) = 72 -3d = 72 - 3(17) = 72 - 51 = 21 inches
answer
the depth of water in the tank will be 21 inches after 17 days
if d = 3
f(d) = 72 -3d = 72 - 3(3) = 72 - 9 = 63 inches
if d = 5
f(d) = 72 -3d = 72 - 3(5) = 72 - 15 = 57 inches
so
if d = 17
f(d) = 72 -3d = 72 - 3(17) = 72 - 51 = 21 inches
answer
the depth of water in the tank will be 21 inches after 17 days
63-57 = 6 inches in 2 days
6/2 = 3 inches per day
17-5 = 12
12*3 =36 inches in 12 days
57-36 = 21 inches after 17 days