t = 0.005x^2 + 0.002x

t = seconds x = objects

Q = How many objects are required to keep the computer busy in exactly 9 seconds?

t = 0.005x² + 0.002x

9 = 0.005x² + 0.002x

0 = 0.005x² + 0.002x - 9

x = - (0.002) ± √ ((0.002) ² - 4 (0.005) (-9))

2 (0.005)

x = - 0.002 ± √ (0.000004 + 0.18)

0.01

x = - 0.002 ± √ (0.180004)

0.01

x = - 0.002 ± 2√ (0.053911)

0.01

x = - 0.2 ± 200√ (0.053911)

The number of objects that is required to keep the computer busy in exactly 9 seconds is - 0.2 ± 200√ (0.053911).