Question

do it for me please​

Answer 1

on reversing the given ap

-100,.......,-6,-4,-2

a= -100

d= a₄-a₃= -2-[-4]=-2+4= 2

n= 12

a₁₂=a+(n-1)*d

  = -100+(12-1)*2

 = -100+11*2

  = -100+22=-78

Answer 2

AP => -2, -4, -6 .........., -100

Here,

First Term (a) = -2

Last Term (b) = -100

Common Difference (d) = -4 -(-2) = -2

Thus, 12th term from the end is:

T = b - (n-1)d

= -100 - (12-1)(-2)

= -100 -11(-2)

= -100 + 22

= -78

Hence, 12th term of the AP from the end is -78.

Therefore, the correct answer is (a) -78.