19. x^2+16x+64
=(x+8)^2
21. x^2-10x+25
=(x-5)^2
Answer:
1
Step-by-step explanation:
s = hours it takes the small pipe on its own.
L = hours it takes the large pipe on its own.
we know the small pipe can do it in 11 hours total, so s = 11, so, how much of the whole job has the small done in 1 hour only?
well, if it takes 11 hours to do the whole thing, in 1 hour it has done only 1/11 of the whole job.
we know both pipes working together can do it in 6 hours flat. So in 1 hour only, both of them have done only 1/6 of the whole thing.
in that 1 hour, how much has the large one done? well, it has only done 1/L of the job.
and you can round that up as needed.
Answer:
9/30 2021
Step-by-step explanation:
:) yw
3p + 2n = 8.25 ....multiply by 2
2p + 3n = 8 .........multiply by -3
-------------------
6p + 4n = 16.5 (result of multiplying by 2)
-6p - 9n = - 24 (result of multiplying by -3)
-------------------add
-5n = - 7.5
n = -7.5 / -5
n = 1.50 .............notebooks cost 1.50 each
2p + 3n = 8
2p + 3(1.50) = 8
2p + 4.50 = 8
2p = 8 - 4.50
2p = 3.50
p = 3.50/2
p = 1.75......pens cost 1.75 each
so 2 pens and 2 notebooks cost : 2(1.75) + 2(1.50) = $ 6.50 <==