Question

2) Find s11 if a=-5 & d = 1​

Answer 1

Answer:

we know,an=a+(n−1)d

so,a7=a+(7−1)d

or,4=a+6(−4)

or,24+4=a

∴a=28

Answer 2

Answer:

an=a+(n-1)X1

5=a+(11-1)X1

5=a+10x1

5=a+10

a=10-5

a= 5