The 2nd and 5th term of a.p are -7 and 56 respectively find the first term. The common ratio. The sum of the five term
4 answers
A student reads 45 pages in 2 h and x pages in 3 h.
please don't tag on your question as an answer to somebody else's.
We would think it has been answered.
We would think it has been answered.
Use your definitions:
a+d = -7
a+4d = 56
subtract them:
3d = 63
d = 21
back in a+d=-7
a+21 = -7
a = -28
sum(5) = (5/2)(-56 + 4(21)) = 70
or
sum(5) = (5/2)(first + last)
= (5/2)(-28 + 56) = 70
check:
our terms are:
-28 -7 14 35 56 ---> add them up to get 70
a+d = -7
a+4d = 56
subtract them:
3d = 63
d = 21
back in a+d=-7
a+21 = -7
a = -28
sum(5) = (5/2)(-56 + 4(21)) = 70
or
sum(5) = (5/2)(first + last)
= (5/2)(-28 + 56) = 70
check:
our terms are:
-28 -7 14 35 56 ---> add them up to get 70
Find the sum of the following series