Question

The 6thterm of an A.P is -10 and its 10thterm is -26. Determine the 15thterm of an AP​

Answer 1

Answer

Tn=a+(n-1)*d

Hence for 6th term we use this formula

T6=a+ (6-1)*d

Like this for 10 term

T10 = a+ 9 *d..

A.T.Q

a+5d=-10

a+9d= -26

Solve simultaneously both equation

By simply subtracting it

We get

a=10 .

d= -4.

Hence

t 15= a+14*d

T15= 10+14*(-4)

T15= -46

This answer

Step-by-step explanation:

Answer 2

Answer:

-46

Step-by-step explanation:

given a6=(-10)

a10=(-26)

a6= a+ 5d (1)

a10=a+9d (2)

(1)-(2) _ 16= {-4}d

therefore d={-4}and a=10

implies a15=a+14d

=10+(-56)={-46}