Question

PLEASE HELP I HAVE ONLY TILL 11:59 TO GET THESE QUESTIONS DONE.

What is the common difference of a 57-term arithmetic sequence where the first term is -25 and the sum is 17,727? (1 points)
Answer

11

11.5

12

12.5


What is the sum of a 14-term arithmetic sequence where the last term is 30 and the common difference is -5? (1 points)
Answer

875

812.5

455

422.5

Answer 1

Then why get behind? Sorry, not trying to be rude, but come on.

Answer 2

im not behind , im just trying to bring my grade up from a high b to an a.

Answer 3

i did all the rest of my questions i cant figure out these ones though

Answer 4

FLVS?

Answer 5

Are you on FLVS?

Answer 6

whats that ?

Answer 7

Lol. Never mind.

Answer 8

sum of an arithmetic sequence is

\[s _{n} = \frac{n}{2}[2a + (n - 1)d]\]

n = 57, a = -25 and s = 17727\[17727 = \frac{57}{2}[2 \times (- 25) + (57 - 1)d]\]

then

622 = -50 + 56d

solve for d

672 = 56d

d = 12

Answer 9

question 2

find th 1st term 1st

using the formula for a term in an arithmetic series

30 = a + (14 -1) (-5)

30 = a - 65

a = 95

then the sum

\[s _{14} = \frac{14}{2}[ 95 + 30]\]

the sum is 875