-3(2+4k)+7(2k-1)

A. 2k-13
b. 8k-13
c. 2k+13
d. 2k-7

9514 1404 393

  A.  2k -13

Step-by-step explanation:

-3(2 +4k) +7(2k -1)

= -6 -12k +14k -7 . . . . . . eliminate parentheses

= (-12 +14)k -6 -7 . . . . . . group like terms

= 2k -13 . . . . matches choice A

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.