Question

first term of an AP is 7 and fourth term is 2​

Answer 1

Step-by-step explanation:

Let a,d and a

n

be the first term,common difference and n

th

term of given AP.

Given, a

4

=3a

⇒a+3d=3a

⇒2a=3d

⇒a=

2

3d

......(1)

a

7

=2a

3

+1 (given)

⇒a+6d=2(a+2d)+1

⇒a+6d=2a+4d+1

⇒a−2d=−1 .......(2)

Substitute a =

2

3d

in equation (2)

2

3d

−2d=−1

⇒−d=−2

⇒d=2

and a =

2

3d

= 3

So, first term is 3 and common difference is 2

Answer 2

Step-by-step explanation:

first term a = 7

fourth term = 2

a + (4-1)d = 2

7 + 3d = 2

3d = 2 - 7

d = -5/3