Question

Find then a and d where 3Rd term is 28 and 7th term is 32

Answer 1

given: 3rd term= 28
it can be written as :
a+2d =28 ---eq1
7th term = 32
it can be written as :
a+6d=32 ----eq2
now , solve both eq.
I solve by elimination method,
a+6d =32
a+2d =28
- - -
0 +4d = 4
d = 1
now put the value of d in eq 1
a +2d = 28
a +2*1 =28
a = 28 - 2
a = 26 .
so ,a=26,d= 1.