Question

which term of AP -2,-7,-12 will be -77? find the sum of this A.P up-to term -77? Please help if anyone can!! I am having my exam plz help.... ​

Answer 1

Answer:

Step-by-step explanation:

a = -2

d = -5

an = -77                  an = a + (n-1)d

-2 + (n-1)(-5) = -77

(n-1)(-5) = -75

n-1 = 15

n = 16

->Therefore, the 16th term of the A.P is -77

sn = n/2 [2a + (n-1)d ]

s16 = 16/2 [ 2(-2) + (16-1)(-5) ]

     = 8 [ -4 -75 ]

     = 8 [-79 ]

      = - 632

-> Therefore, the sum of first 16 terms is - 632

Answer 2

hope u like it plz mark me as brainlist