Answer:
126 tiles
Step-by-step explanation:
The while tiles are 3/4 of a foot (or 9 inches) x 9 in, so their area is 81 sq in. There are 14 blue tiles, so 14 x 81 = 1134 sq inches that need to be covered.
Each tiles is 3 x 3, so its area is 9 sq in. 1134 / 9 = 126 tiles
640/79=8...8
79 goes through 640 8 times
= 3x(2x^2 - 4x - 5) - 6(2x^2 - 4x - 5)
= 6x^3 - 12x^2 - 15x - 12x^2 + 24x + 30
= 6x^3 - 24x^2 + 9x + 30 (answer)
Answer:
a) 
b)
Step-by-step explanation:
Data
Brine a (Ba)

Brine b (Bb)

we have that per every minute the amount of solution that enters the tank is the same as the one that leaves the tank (15 Lt / min)
, then the amount of salt (y) left in the tank after (t) minutes: 
Finally:
a) 
b) 
being y(t) the amount of salt (y) per unit of time (t)