P=-4b^2 + 6b - 9 q= 7b^2 - 2b -5 p- q =

P = -4b^2 + 6b - 9

Q = 7b^2 - 2b - 5

P - Q = ?

Combine like terms (which involve b^2, b and constants):

P = -4b^2 + 6b - 9

Q = 7b^2 - 2b - 5

P - Q = -4b^2 - 7b^2    + 6b - (-2b)    - 9 - (-5), or:

P - Q     =  -11 b^2             + 8b                  - 4

it would take 7/10 of an hour too fill the pool.

step-by-step explanation:

20%

step-by-step explanation: