Question

докажите тождество (х-у)^2+2ху+х^2-у^2=х*2х

Answer 1

x^2 - 2xy + y^2 + 2xy + x^2 - y^2 = 2x^2
здесь 2xy и y^2 kiskaradi
ostaetsya
x^2+x^2 = 2x^2
2x^2=2x^2