Question

T5 = 20
T8 = 15
a=
d = ​

Answer 1

Answer:

a=80/3

d=-5/3

Step-by-step explanation:

Given that :-

T5=20

=>a+4d=20------(1)

T8=15

=>a+7d=15-------(2)

from (1)&(2)

a+4d=20

a+7d=15

(-)

-----------

0+-3d=5

------------

-3d=5

= d=5/-3

d=-5/3

and from (1)

a+4(-5/3)=20

=>a-(20/3)=20

=>a=20+(20/3)

=>a=(60+20)/3

=>a=80/3

First term=80/3

Common difference=-5/3