Question

X²+y²=26, xy=3, then
(a) x+y=?
(b) x-y=?

Answer 1

x^2+y^2=(x+y)^2-2*x*y

            =(x-y)^2+2*x*y

Here we can find out the value of (x+y) and (x-y) using the above mentioned formula and finally we obtain,

                x+y=4*sq. root of 2

                x-y=2*sq. root of 5