已知x的二次方减x减3等于0,求x四次方减2x三次方加3x二次方减7x减1的值
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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
笨笨的解法:x^2+2x-3=0(x+3)(x-1)=0可得x=1,-33x^2+6x-4=?13+6-4=5-327-18-4=5另一种解法:x^2+2x-3=0集体乘33x^2+6x-9=03x^
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^2+X^-2=3则:(X^2+X^-2)^2=9得到X^4+2+X^-4=9解得X^4+X^-4=7注:X^-2为X的-2次方,X^2为X的平方.望采纳
化简可得3再问:怎么化简啊再答:(x2/y2)+(y2/x2)=[(xy+y2)/y2]+[(x2-xy)/x2]=(x/y)-(y/x)+2=[(x2-y2)/xy]+2=1+2=3化简可得3
x^2+3x-2=0x^2+3x+9/4=17/4(x+3/2)^2=17/4x+3/2=√17/2x=(-3+√17)/2或x+3/2=-√17/2x=(-3-√17)/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+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-y²=(x+y)(x-y)=6因为x+y=3所以(x+y)(x-y)/(x+y)=6/3x-y=2
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