作业帮X的平方等于负1求X
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/11 20:29:29
得到:X^2-15X=-56X^2-15X+56=0(x-7)(x-8)=0所以X=7或者x=8
3x^2y-xy^2=xy(3x-y)将x=-1/2y=1代入有-1/2*1*[3*(-1/2)-1]=-1/2*(-5/2)=5/4
x²-x-1=0∴x²-x=1-x³+2x²+2012=-x(x²-x)+x²+2012=-x+x²+2012=1+2012=20
=（-3）^2-1-2(-1）-5+（-3+1）^2=9-1+2-5+4=9
x等于根号2加1,y等于根号2减1所以x+y=√2+1+√2-1=2√2x-y=(√2+1)-(√2-1)=2所以x²-y²=(x+y)(x-y)=2√2×2=4√2
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
x+1/x=a平方,x^2+1/x^2+2=a^2x^2+1/x^2=a^2-2平方,x^4+1/x^4+2=(a^2-2)^2x^4+1/x^4=a^4-4a^2+2x^2+1/x^2+x^4+1/
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/
x²-3x=-1即x²+1=3xx+1/x=3
x+1/x=-2x^2+1/x^2=?（x+1/x)^2=4x^2+1/x^2+2=4解得：x^2+1/x^2=2
x=10y=11x^2=100(-y)^2=121x+y=21x=1y=1/2x^2=1(-y)^2=1/4x+y=3/2x=5y=-6x^2=25(-y)^2=36x+y=-1从上面式子中可以看出,
x²-y²=-1x+y=1/2求x-yx²-y²=（x+y)*（x-y)=-1∴1/2*(x-y)=-1x-y=-2很高兴为您解答疑难,请采纳,如有疑问请追问,
x(x+1)*(x+1)-x=x(x*x+2x+1)-x=x*x*x+2x*x+x-x=x*x+2x*x=19+19*2=57
直线l:y=-x+a,与y=b/ax消去y解得yB=ab/(a+b)y=-x+a,与y=-b/ax消去y解得yC=ab/(b-a)∵向量AB=1/2向量BC∴yC=3yBab/(b-a)=3ab/(a
【x+1】的平方+x【1-x】,=x²+2x+1+x-x²=3x+1当x=-2时原式=-6+1=-5
x²+3x=-2.(x+1)(x+2)=0,即：x=-1或x=-2.当x=-1时,（x➕1）²-（2x➕1）（x➕2）=1当x=-2时,（
x^2-x=-8x^2-x+8=0根据判别式1-32《0所以无解.