Question

please give this answer

Answer 1

x+y/x-y= u/v
by componendo and dividendo
or, x/y= u+v/u-v........equation 1

multiplying both sides by x/y,
x/y(x+y/x-y)= x/y(u/v)
using equation 1 we can write,
or, x/y(x+y/x-y)= u+v/u-v(u/v)
or, x^2+xy/xy-y^2= u^2+uv/uv-v^2...............[proved]