Question

cacuate the sum of 35 term in an AP , whose 4 term is 16 and 9 term is 31..... plzz solve fast I will add you as a brainlist​

Answer 1

Answer:

Given :

t4 = 16

t9 = 31

Solution :

t4 = a + 3d = 16 eqn 1

t9 = a + 8d = 31 ________ eqn2

Subtract eqn 1 and 2

a + 8d = 31

-

a + 3d = 16

By solving this

Solve Properly

d = 3 & a = 9

Put value in Sn = n/2(2a + (n -1 )d)

= 35/2 [18 + 34 × 3]

= Which is equal to 2038

Hope this help you

• I leave some calcution solve it properly