因式分解法解下列方程 1、用因式分解法解下列方程:(1)3y^2-5y=0 （2）4x^2=12x (3)x^2+9=-6x (4)9x^2=(x-
x^3-3x^2-13x+15
=x^3-3x^2+2x-15x+15
=x(x^2-3x+2)-15(x-1)
=x(x-2)(x-1)-15(x-1)
=(x-1)[x(x-2)-15]
=(x-1)[x^2-2x-15]
=(x-1)(x-5)(x+3) 这样的