Question

if the third term of ap is 1 and 5th term is 7find the term of first 10 series​

Answer 1

Answer:

Given:a3=1;a5=7

To find:a10

Solution:a+2d=1 -----(1)

a+4d=7 -----(2)

Now, subtract (2) equation from (1) equation also change the signs

a+2d=1

a+4d=7

=-2d=-6

=2d=6

=d=6/2

=d=3

put the value of d in (1) equation

a+2d=1

a+3(3)=1

a+9=1

a=1-9

a=-8

Now using formula,an=a+(n-1)d

a10=-8+(10-1)3

a10=-8+30-3

a10=22-3

a10=19

Therefore,tenth term is 10