Y=X的平方加2XZ加3
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由题意可以知道:x/3=y=z/4,所以x=3y,z=4y.xy+xz+yz=76把xz都换成y可以得到:3y^2+12y^2+4y^2=76解得:y^2=4x^2=(3y)^2=36z^2=(4y)
A+B=2x²-3xy+y²+x²+2xy-3y²=3x²-xy-2y²A-2B=2x²-3xy+y²-2(x²
x=t;y=2t;z=3t;xy+yz+xz=2t^2+6t^2+3t^2=66t^2=62x^2+12y^2+9z^2=2t^2+48t^2+81t^2=131t^2=786
2x²+3xy-2y²=0(2x-y)(x+2y)=02x=y或x=-2y
x²+y²+z²-xy-yz-xz=1/2[(x-y)²+(y-z)²+(x-z)²]=1/2(4²+2²+6²
x^2+2xy+y^2=25===>(x+y)^2=5^2===>x+y=±5(x-y)^2-3x+3y+2=0===>(x-y)^2-3(x-y)+2=0===>[(x-y)-1]*[(x-y)-2
∵X²-2√2X+2+Y²+2√3X+3=0﹙X-√2﹚²+﹙Y+√3﹚²=0∴X=√2,Y=-√3∴ㄧX+Yㄧ=√2+√3
(x-3)^2+│y+1│+z^2=0推出x-3=0,x=3;y+1=0,y=-1z^2=0,z=0则x^2-2xy+12xz-5x^2+3xy-z^2-8xz-2x^2=x^2-2xy-5x^2+3
求根法:x^2+xy-2y^2+2x+7y-3=x^2+x(y+2)-2y^2+7y-3,△(x)=(y+2)^2-4(-2y^2+7y-3)=9y^2-24y+16=(3y-4)^2,x1=[-(y
x²-y²=(x²+xy)-(xy+y²)=3-(-2)=5再问:那么x的平方加4xy加3y的平方=2x的平方减xy减3y的平方=再答:x的平方加4xy加3y的
x^2-4xy+4y^2-3x+6y+2=(x-2y)^2-3(x-2y)+2=(x-2y-1)(x-2y-2)
(X+Y+Z)的平方就是4,展开就是X的平方+Y的平方+Z的平方+2XY+2XZ+2YZ=4.XY+YZ+XZ=5.则2XY+2YZ+2XZ=10.故答案就是-6
(X-Y)+(Y-Z)=X-Z=4(X-Y)^2+(Y-Z)^2+(X-Z)^2=X^2-2XY+Y^2+Y^2-2YZ+Z^+X^2-2XZ+Z^2=2(X^2+Y^2+Z^2-XY-YZ-XZ)=
x^2-2x+y^2+8y+17=0(x-1)^2+(y+4)^2=0x=1;y=-4;
∵x-y=5,y-z=3,∴x-z=8由x-y-5,得:x2-2xy+y2=25同理,可得:y2-2yz+z2=9x2-2xz+z2=64三式相加,得:2x2+2y2+2z2-2xy-2yx-2xz=
x的平方加y的平方加2x-6y+10=0即:(x+1)^2+(y-3)^2=0所以:x=-1,y=3.所以:x+y=2.
如果x的平方加xy等于2,y的平方加x的y等于-1,则x的平方-y的平方=?x的平方加2xy加y的平方等于多少?x²+xy=2y²+xy=-1x²+xy-y²-
由题意可得x²+y²+2x+6y+10=0(x+1)²+(y+3)²=0所以x=-1,y=-3
y=3x^2-x+2--->3x^2-x+(2-y)=0判别式不小于0,故(-1)^2-4×3×(2-y)>=0--->-23+12y>=0--->y>=23/12故函数y的值域为[23/12,+无穷