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x的平方减5x加2等于0

X^2 -5X+2=0(x-5/2)^2 -25/4 +2=0(x-5/2)^2=17/4 x-5/2=±(√17)/2 x=(5±√17)/2

x^2-5x+2=0 x=(-5±√(5^2-4*2))/2 x=(-5±√17)/2 望采纳!

X的立方加2X的平方减5X加2等于0x-x+2x-4x+2=0x(x-1)+2(x-2x+1)=0x(x+1)(x-1)+2(x-1)=0(x-1)[x(x+1)+2(x-1)]=0(x-1)(x+x+2x-2)=0(x-1)(x+3x-2)=0则x-1=0或x+3x-2=0则x=1或x=(-3+√17)/2或x=(-3-√17)/2

x的平方减2根号5x加2=0 x的平方减2根号5x加5=3 (x-根号5)平方=3 X-根号5=根号3或-根号3 X1=根号五+根号3,X2=根号5-根号3

x-5x+2=0那么由韦达定理可得:x1+x2=5x1x2=2所以x1+x2-x1x2=5-2=3

似乎是:根号5加根号三或根号5减根号3

x的平方减5x等于负6,由此可知x等于3.把6移过去,形成一个等式.

求根公式:2x-5x+2=0 (2x-1)(x-2)=0 x1=1/2,x2=2 =0.5/2

x方减5x加2=0求x的两个根 解:x-5x+2=0 x=[5±√(25-8)]/2=(5±√17)/2

若x平方减5x加2等于0,则x的4次方减3x的立方减7x的平方减x加7等于x^2-5x+2=0x^2=5x-2因为x^4-3x^3-7x^2-x+7=(x^4-3x^3-7x^2)-x+7=(x^2)(x^2-3x-7)-x+7=(5x-2)(5x-2-3x-7)-x+7=(5x-2)(2x-9)-x+7=10x^2-4x-45x-x+7+18=10x^2-50x+7+18=10(5x-2)-50x+25=50x-20-50x+25=25-20=5整体代入法

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