You can put this solution on YOUR website! in an arithmetic sequence the 1st term=a & common difference=d
the 6th term = x =a+(6-1)d
or a+5d=x .................1
the 11th term= y =a+(11-1)d
or a+10d=y
or a=y-10d.................2
putting the value of a from 2 in 1
y-10d+5d=x
or y-5d=x
or d=(y-x)/5........3
from 2
a=y-10*(y-x)/5=y-2y+2x=2x-y.....4
so 1st term=a=2x-y
2nd term=a+d=2x-y+(y-x)/5=(10x-5y+y-x)/5=(9x-4y)/5
ans
