左边直接开方开不出来,必须先把它拆开:
(x-2)(2x-3)
=2x^2-3x-4x+6
=2x^2-7x+6
∴2x^2-7x+6=3
x^2-(7/2)x=(3-6)/2=-3/2
x^2-(7/2)x+(7/4)^2=(7/4)^2-3/2=25/16
(x-7/4)^2=25/16
x-7/4=±√(25/16)=±5/4
x=7/4±5/4=(7±5)/4=3或1/2
(X-2)(2X-3)=3
2x²-7x+6=3
2x²-7x+3=0
(2x-1)(x-3)=0
2x-1=0 x-3=0
x=1/2或x=3
方程变成:
2x^2-7x+3=0
x^2-7x/2+3/2=0
x^2-2*7x/4+49/16-49/16+3/2=0
(x-7/4)^2=25/16
x1=7/4+5/4=3
x2=1/2