(х+y)=0
(x-y)=1
0^2=0
1^2=1
0-1=-1
(x+y)^2-(x-y)^2=x^2+2xy+y^2-x^2+2xy-y^2=2xy+y^2+2xy-y^2=4xy+y^2-y^2=4xy4xy=4*0,5*(-0,5)=-2*0.5=-1
(х+y)=0
(x-y)=1
0^2=0
1^2=1
0-1=-1
(x+y)^2-(x-y)^2=x^2+2xy+y^2-x^2+2xy-y^2=2xy+y^2+2xy-y^2=4xy+y^2-y^2=4xy
4xy=4*0,5*(-0,5)=-2*0.5=-1