Question

Find the 13th term of the A.P. -5, -10, -15,-20,....?​

Answer 1

Answer:

-65

Step-by-step explanation:

Here, a=-5

d=t2-t1=-10-(-5)=-5

n=13

We know that,

tn = a+(n-1)d

Thus,

t13=-5+(13-1)-5

= -5+12×(-5)

= -5+(-60)

t13= -65

Answer 2

Step-by-step explanation:

A =a+(13-1)×d, d= a2-a1 = -10+5= -5, a= -5

13

A13 = -5 + 12× (-5)

= -5 -60

= -65