Asked by Okafor providence MC

The first and last term of AP are 79and -5 if the sun is 814 find
The number of terms on the AP
The common difference
Answered by mathhelper
sum(n) = n(first + last)/2
814 = n(79-5)/2
814 = 37n
n = 22

term(22) = a + 21d
-5 = 79 + 21d
d = -4