用因式分解法解下列方程:(1)(4x-1)(5x+7)=0.(2)3x(x-1)=2-2x.(3)(2x+3) 2 =4(2x+3).(4)2(x-3) 2 =x 2 -9.
(1))(4x-1)(5x+7)=0, 4x-1=0,5x+7=0, x 1 =
(2)3x(x-1)=2-2x, 3x(x-1)+2(x-1)=0, (x-1)(3x+2)=0, x-1=0,3x+2=0, x 1 =1,x 2 =-
(3)(2x+3) 2 =4(2x+3), (2x+3) 2 -4(2x+3)=0, (2x+3)(2x+3-4)=0, 2x+3=0,2x+3-4=0, x 1 =-
(4)2(x-3) 2 =x 2 -9, 2(x-3) 2 -(x+3)(x-3)=0, (x-3)[2(x-3)-(x+3)]=0, x-3=0,2(x-3)-(x+3)=0, x 1 =3,x 2 =9. |