a(b-c)-c(c-b) = a(b-c)-(-c(b-с))= a(b-c)+c(b-с) =(b-с)(a+c)
2b(x-y)-(y-x)= 2b(x-y)- (-(x-у))= 2b(x-y)+(x-у) =(x-y)(2b+1)
a(b-c)-c(c-b) = a(b-c)-(-c(b-с))= a(b-c)+c(b-с) =(b-с)(a+c)
2b(x-y)-(y-x)= 2b(x-y)- (-(x-у))= 2b(x-y)+(x-у) =(x-y)(2b+1)