Question

(x-y)^2+(x+y)^2-2(x+y)(x-y)=4x^2

Answer 1

(х-у)²+(х+у)²-2(х+у)(х-у)=4х²

х²-2ху+у²+х²+2ху+у²-2х²+2у²-4х²=0

4у²-4х²=0

у²=х²

|у|=|х|