1、(2x+1)(x-3)=4(x-3)
(x-3)(2x+1-4)=0
(x-3)(2x-3)=0
x=3或x=3/2
2、x²-4x=8
(x-2)²=12
x-2=±2√3
x=2±2√3
x=2+√3或x=2-√3
3、4x²-4x+5=0
x²-x=-5/4
(x-1/2)²=-1