初三数学题,用公式法解1.x²-√3x-1/4=02.3x²-6x-2=03.4x²-6x=05.x(2x-4)=5-8x
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初三数学题,用公式法解1.x²-√3x-1/4=02.3x²-6x-2=03.4x²-6x=05.x(2x-4)=5-8x
初三数学题,用公式法解
1.x²-√3x-1/4=0
2.3x²-6x-2=0
3.4x²-6x=0
5.x(2x-4)=5-8x
初三数学题,用公式法解1.x²-√3x-1/4=02.3x²-6x-2=03.4x²-6x=05.x(2x-4)=5-8x
x²-√3x-1/4=0 x²-√3x+3/4=1/4+3/4 (x-√3/2)²=1 x-√3/2=1或 x-√3/2=-1 x=1+√3/2或x=√3/2-1
.3x²-6x-2=0 x²-2x-2/3=0 x²-2x+1=1+2/3 (x-1)²=1+2/3 x-1=√(1+2/3) 或 x-1=...
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x²-√3x-1/4=0 x²-√3x+3/4=1/4+3/4 (x-√3/2)²=1 x-√3/2=1或 x-√3/2=-1 x=1+√3/2或x=√3/2-1
.3x²-6x-2=0 x²-2x-2/3=0 x²-2x+1=1+2/3 (x-1)²=1+2/3 x-1=√(1+2/3) 或 x-1=-√(1+2/3) x=1+√(1+2/3)或 x=1-√(1+2/3)
4x²-6x=0 2x²-3x=0 x(2x-3)=0 x=0或x=3/2
x(2x-4)=5-8x 2x²+4x=5 x²+2x=5/2 x²+2x+1=5/2+1 (x+1)²=7/2 x+1=√7/2或x+1=-√7/2 x=√7/2-1或x=-√7/2-1
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1、判别式=3-4*1/4=2
x=√3±√2/2
2、判别式=36+4*3*2=60
x=6±2√15/6=3±√15/3
3、判别式=0
x1=0,x2=3/2
4、判别式=16+4*2*5=56
x=-4±2√14/4=2±√14/2
x^2+4x+8=2x+11化简一下得:x^2+2x-3=0(x+3)*(x-1)=0所以:x=-3或者x=1