The 6th term of an arithmetic sequence is x while

Question

the 11th is y find the 1st 2 terms

Answer 1

a+5d = x
a+10d = y
subtract them
5d = y-x
d = (y-x)/5
and
a + 5(y-x)/5 = x
a + y - x = x
a = 2x - y

first two terms are:
t1 = 2x-y
t2 = 2x-y + (y-x)/5 = (10x - 5y + y-x)/5
= (9x - 6y)/5