Please help me I promise I will mark brainliest, I need an answer asap f(x) = 3x + 9, g(x) = 5x^2 Find (f + g)(x). A). -5x^2 + 3x + 9 B). Quantity three x plus 9 divided by five x squared. C). 15x^3 + 45x D). 5x^2 + 3x + 9

D

Step-by-step explanation:

(f+g)(x) = f(x) + g(x)

=3x + 9 + 5x²

=5x² + 3x + 9

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.

5

step-by-step explanation: