Question

(v) given d=5, S, = 75, find a and a9​

Answer 1

Step-by-step explanation:

s?=75 what is the value of n

Sn=1/2{2a,+(n-1)d}

75=1/2{2a+(n-1)5}

150=2a+(n-1)5

2a=150-(n-1)5

a=1/2{(n-1)5}.........eq1

put value of n u will get value of a

now,

tn=a+(n-1)d

t9=a+(9-1)5

t9=a+40

put value of a from eq and u will get answer