Question

if the sum of first four terms of an ap is 8 then find its first term​

Answer 1

Answer:

first term is 2

Step-by-step explanation:

Let the terms are-

a-d,a,a+d,a+2d

by the given conditions

a-d+a+a+d+a+2d=8

4a+2d=8

2(2a+d)=8

2a+d=8/2

2a+d=4

a-d+a+2d=a+a+d

d=d

d=0

2a+d=4

2a+0=4

a=4/2

a=2

Answer 2

Step-by-step explanation:

let the 4 numbers be a,b,c ,k

by data ,

we have :a+b+c+d=8

Sn=n/2 (a+An)

here .,n=4

a=a

An=k

so,8=4/2 (a+k)

8=2 (a+k)

4=a+k

3

k=4-a...............

An=a+(n-1)d

An=k

n=4

d=?

so.k=a+(4-1)d

k=a+3d............2

k-a=3d

k-a=4-2a

k=4-a