Question

find a30-a20 for ap -9,-14,-19,-24,...

Answer 1

Hi ,

-9 , - 14 , - 19 , -24 ,...., is an A.P

First term = a = -9

Common difference = a2 - a1

d = -14 - ( - 9 )

= -14 + 9

d = -5

nth term = an = a + ( n - 1 ) d

1 ) a30 = a + 29d

= -9 + 29 ( -5 )

= -9 - 145

= - 154 ----( 1 )

2 ) a20 = a + 19d

= - 9 + 19 ( -5 )

= -9 - 95

= - 104----( 2 )

Therefore ,

a30 - a20 = -154 - ( - 104 )

= - 154 + 104

= - 50

I hope this helps you.

:)

Answer 2

Step-by-step explanation:

here a = -9

d = a2 - a1

= [-14] - [-9]

= -14+9

=-5

a30 - a20

[a+29d]+[a+19d]

a+29d-a-19d

10d [therefore d = -5 ]

10[-5]

-50

I hope this answer helps you to solve the problem