3x-12x^2解公式式 (1)3x-12x^2 (2)x(x-y)+y(y-x)

3x-12x^2解公式式 (1)3x-12x^2 (2)x(x-y)+y(y-x)

3x-12x^2=3x(1-4x)
(2)x(x-y)+y(y-x)=(x-y)^2