x方减x等于1-搜答案-灵鹊做题网

x²+3x-1=0x²=-3x+1所以x³=x×x²=x(-3x+1)=-3x²+x=-3(-3x+1)+x=10x-3原式=(10x-3)+5(-3

x²-x-1=0,x≠0两边同除以x：x-1-1/x=0x-1/x=1,两边平方：x²+1/x²-2*x*1/x=1x²+1/x²-2=1x²

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

x²-3x+1=0得x=(3±√5)/21/x=(3-√5)/2或(3+√5)/2x+1/x=3x^4+1/x^4=(x²+1/x²)²-2=[(x+1/x)&

x-1=√3x²-2x+1=3x²-2x=2原式=x³-2x²-x²+2x+x=x(x²-2x)-(x²-2x)+x=2x-2+x

x^2-3x+1=0x^2=3x-1x^2+1=3xX的4次方+X的方+1分之X的方=x^2/[(x^2+1)^2-x^2]=x^2/(9x^2-x^2)=1/8

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=1/(2+√3)xy=1y=(2+√3)x=1/(2+√3)x=(2-√3)/(2+√3)(2-√3)x=2-√3(x^2y-xy^2)/(x^2-y^2)=xy(x-y)/(x+y)(x-y)=

x+1/x=3x^2+1/x^2=(x+1/x)^2-2=9-2=7

x²+5x-1=0除以x得x+5-1/x=0x-1/x=5x²+1/x²=(x-1/x)²+2=5²+2=27x^4+1/x^4=(x²+1

正负根号5

X方减3X等于130

x^2-3x=130x^2-3x-130=0(x-13)(x+10)=0x=13或x=-10

16乘x的四次方减1=（2x）的四次方-1=[（2x）平方-1][（2x）平方+1]=(2x-1)(2x+1)（4x平方+1)

x^2+y^2>1?是x^2+y^2

x+y=1（1）.(x+y)(x-y)=9x-y=9（2）（1）+（2）:2x=10x=5,（1）-（2）:y=-4再问：能再详细点么(>﹏

令a=2^x则2^(2x+2)=2^2x*2²=4a²所以4a²-a=14a²-a-1=0a=(1±√17)/8a=2^x>0所以2^x=(-1+√17)/8x

（x^2+y^2）*(x^2-1+y^2)-12=0可以设x^2+y^2=z那么有z(z-1)=12z^2-z-12=0(z-4)(z+3)=0z=4或z=-3但z是平方和一定大于0所以z=4记得采纳

x-1/x=1x^2+1/x^2=(x-1/x)^2+2=1+2=3x^3-1/x^3=(x-1/x)(x^2+1+1/x^2)=1*(3+1)=4不懂可追问,有帮助请采纳,谢谢!再问：x^3-1/x

x方-y方+2x+1等于?

x方-y方+2x+1=(x^2+2x+1)-y^2=(x+1)^2-y^2=(x+y+1)(x-y+1)