Question

The 5th term of an AP is -3 and its common difference is -4. The sum of the first 10 term is

Answer 1

Step-by-step explanation:

a5 = a + 4d = -3

=> a + 4(-4) = -3

=> a - 16 = -3

=> a = -3 + 16 => 13

S10 = 10/2 [ 2×13 + 9 × (-4) ]

=> 5 [ 26 - 36 ]

=> 5 × -10

=> - 50

Answer 2

Answer:

-50

Step-by-step explanation:

a5 is equal to minus 3

so a+4d = -3 --1

d= -4 --2

on solving 1 and 2 we get

a+4* -4 = -3

a. = 13

S = n/2(2a+(n-1)d)

S = 10/2(2*13+9*-4)

S= 5(26-36)

S = -50