已知x的二次方减3x减1等于0
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当x=0时,等式不成立,所以x≠0等式两边除以x得:x+1/x=3x^3+1/(x^3)=(x+1/x)(x^2-1+1/x^2)=(x+1/x)(x^2-1+1/x^2+2-2)=(x+1/x)[(
(1)X²-5X+1=0,X²+1=5X由于可以判断X不等于0,所以两边同时除以XX+1/X=5X²+X^(-2)=X²+1/X²=(X+1/X)&s
x的二次方减3x加1等于0x-3+1/x=0x+1/x=3(x+1/x)^2=9x^2+1/x^2+2=9x^2+1/x^2=7
由(1)x²-xy=5(2)y²+xy=-2∴(1)+(2)得:x²+y²=3.
由已知得x²+1=3x即(x²+1)/x=x+1/x=3x²+1/x²=(x+1/x)²-2*x*(1/x)=3²-2=7x的四次方+1/x
已知x二次方减去5x加1等于0解得:x1=(5+根号(21))/2,x2==(5-根号(21))/2而(x^2+1/(x^2))=(x+1/x)*(x+1/x)-2=(5*(5+根号(21))/(5+
因为x²+3x-1=0所以x^3+4x²+2x+18=x^3+3x²-x+x²+3x+18=x(x²+3x-1)+x²+3x+18=x
即x²+4x=4所以原式x³+4x²+x²-2=x(x²+4x)+x²-2=4x+x²-2=4-2=2
x×x×x-3×x×x=0x×x²-3×x²=0x×x²=3×x²x×x²÷x²=3×x²÷x²x=3
x^2+x-1=0x^2+x=1x^3+2x^2+3=x^3+x^2+x^2+3=x(x^2+x)+x^2+3=x+x^2+3=1+3=4
x^2-x-1=0x^2-x+0.25-1.25=0(x-0.5)^2=1.25x-0.5=±0.5√5x=0.5(1±√5)
x/y=3x=3y原式=[(3y)²+2*3y*y-3y²]/[(3y)²-3y*y+y²]=(9y²+6y²-3y²)/(9y&
x+1/x=3(x+1/x)^2=9x^2+1/x^2+2=9x^2+1/x^2=7x^2+1/x^2-2=7-2(x-1/x)^2=5x-1/x=±√5x^2-1/x^2=(x+1/x)(x-1/x
x²-x-1=0两边同乘以xx-1-1/x=0x-1/x=1(x-1/x)²=1x²+1/x²-2=1x²+1/x²=3x²+1/
2x^2-6x-5=2(x^2-3x-1)-5+2=0-3=-3
x=2y=1
x^2-3x+1=0∵x≠0,∴(方程两边同时除以x)x-3+1/x=0即x+1/x=3∴X的二次方+X的二次方分之一=(x+1/x)^2-2=7
x^2-xy=14xy-3y^2=2求x^2+3xy-3y^2因为x^2-xy=1所以x^2=1+xy带入原式得4xy+1-3y^2因为4xy-3y^2=2将其带入原式得2+1=3
解-(-x²)³×(-x²)²-x×(-x³)³——是这个吗=x^6×x^4-x×(-x^9)=x^10+x^10=2x^10
∵丨X-1丨+(y+3)的二次方=0∴x-1=0y+3=0x=1y=-3∴(xy)的二次方=(-3*1)²=9