解方程:(1)2x²+3x-1=0 (2)x²+3=2√3x (3)(2x+1)²=(x-3)²
问题描述:
解方程:(1)2x²+3x-1=0 (2)x²+3=2√3x (3)(2x+1)²=(x-3)²
答
(1)2x²+3x-1=0
x=[-3-√(9+8)]/2*2=(-3-√17)/4或(-3+√17)/4
(2)x²+3=2√3x
(x-√3)^2=0
x=√3
(3)(2x+1)²=(x-3)²
4x^2+4x+1=x^2-6x+9
3x^2+10x-8=0
(3x-2)(x+4)=0
x=2/3或x=-4
答
2x²+3x-1=0
2(x²+3/2x+9/16)=17/8
(x+3/4)²=17/16
x+3/4=±√17/4
x1=-3/4+√17/4
x2=-3/4-√17/4
x²+3=2√3x
x²-2√3x+3=0
(x-√3)²=0
x=√3
(2x+1)²=(x-3)²
(2x+1)²-(x-3)²=0
(2x+1+x-3)(2x+1-x+3)=0
(3x-2)(x+4)=0
x1=2/3 x2=-4