Question

(v) Given d = 5, S9 = 75, find a and a9.​

Answer 1

Step-by-step explanation:

d=5,s

9

=75

s

9

=

2

9

[2a+(9−1)5]

75=

2

9

[2a+40]

150=9[2a+40]

150=18a+360

150−360=18a

−210=18a

18

−210

=a

a=

3

−35

a

9

=a+(9−1)5

a

9

=

3

−35

+40

a

9

=

3

−35+120

a

9

=

3

−85

Answe