Question

x2十2x十4十x十2xx一2

用公式法解下列方程 xx十x一2=0 xx一4x十2=0 4xx一3x一5=x一2 3x(x一3)
用公式法解下列方程
xx十x一2=0
xx一4x十2=0
4xx一3x一5=x一2
3x(x一3)=2(x一1)(x十1)

Answer 1

(1)(x+2)(x-1)=0
x=-2,x=1
(2)(x-2)(x-2)=2
x=2+根号下2,x=2-根号下2
(3)4xx-4x-3=0
(2x-3)(2x+1)=0
x=3/2,x=-1/2
(4)3xx-9x=2xx-2
xx-9x+81/4=-2+81/4
(x-9/2)(x-9/2)=73/4
x=9/2+根号下73/4,x=9/2-根号下73/4