X^2-2x=0
x(x-2)=0
x=0 x-2=0
x=2
(x-2)(x+4)*4+3(x+4)=x(4x+1)
4x^2+8x-32+3x+12=4x^2+x
4x^2-4x^2+8x+3x-x-32+12=0
10x-20=0
10x=20
x=20/10
x=2
<span> (x-y)(x+y)-(a-x+y)(a-x-y)-a(2x-a)=</span>x2-y2-((a-x)2-y2)-2ax+a2 = x2-y2-(a2-- 2ax+x2-y2)-2ax+a2 = x2-y2-a2+2ax-x2+y2-2ax+a2=0. Тождество доказано.
на фото......................................