Question

please solve in note book please !!!​

Answer 1

Step-by-step explanation:

so using formula for n th term 

a = first term

n = no. of terms 

d = common difference

So given

a + (3-1)d + a (7-1)d = 6

2a + 8d = 6

a + 4d = 3

a = 3 - 4d

(a + 2d)(a + 6d) = 8 

(3 - 2d)( 3 + 2d) = 8   {substituting a = 3 - 2d}

9 - 4d² = 8

d = +1/2 and - 1/2

so when d = +1/2 then a = 3 - 2 = 1 and when d = -1/2  a = 3 + 2 = 5

so using formula for 

when d = +1/2

Similarly when d = -1/2

Answer 2

The answers are 76 and 20...