mathematics

find x and y
x-y=3
x^2+y^2=29

If x-y=3 then x=3+y
so
(3+y)^2+y^2=29

now expand the brackets, simplify, bring 29 over to the LHS and then sove as a quadratic.
why don't you have a go a this now.
if you get stuck I'll help some more.