初二数学一元二次方程计算题(用公式法)

来源:百度知道 编辑:UC知道 时间:2024/05/22 08:08:20
(1)x^2-(1+2根号3)x+根号3-3=0

(2)x^2-(根号3+根号2)x+根号6=0

(1)x^2-(1+2根号3)x+根号3-3=0
(1+2根号3)方-4(根号3-3)
=1+12+4根号3-4根号3+12
=25
X1=(1+2根号3+5)/2=3+根号3
X2=(1+2根号3-5)/2=-2+根号3

(2)x^2-(根号3+根号2)x+根号6=0
(根号3+根号2)方-4根号6
=3+2+2根号6-4根号6
=(根号3-根号2)方
X1=(根号3+根号2+根号3-根号2)/2=根号3
X2=(根号3+根号2-根号3+根号2)/2=根号2

1,x^2-(1+2根号3)x+根号3-3=0
x^2-2(1/2+根号3)x+(1/2+根号3)^2-(1/2+根号3)^2+根号3-3=0
(x-1/2-根号3)^2=-根号3+3+(1/2+根号3)^2
(x-1/2-根号3)^2=25/4
x-1/2-根号3=2/5
x=3+根号3
第二个同理
x^2-(根号3+根号2)x+根号6=0
x^2-2(根号3/2+根号2/2)x+(根号3/2+根号2/2)^2-(根号3/2+根号2/2)^2+根号6=0
(x-根号3/2-根号2/2)^2=(5-2根号6)/4
(x-根号3/2-根号2/2)^2=(根号3-根号2)^2/4
x=根号3-根号2