已知X加3Y减10=0,试求x和y的值
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已知x的平方加3xy减4y的平方等于0,(y不等于0),试求x-y/x+y即:X^2+3xy-4y^2=(x+4y)(x-y)=0x+4y=0或x-y=0;x=-4y或x=y将x值代入算式x-y/x+
应该是x^2-2x+y^2+6y+10=0配方:x^2-2x+1+y^2+6y+9=0(x-1)^2+(y+3)^2=0得x=1y=-3所以x+y=-2
x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0(x-1)^2=0x-1=0x=1(y+3)^2=0y+3=0y=-3x+y=1-3=-2
x的三次方+3x的平方y-2x-6y=x²(x+3y)-2(x+3y)=(x+3y)(x²-2)=0
x^2+2x+y^2-6y+10=0=(x^2+2x+1)+(y^2-6y+9)=0=(x+1)^2+(y^2-6y+3^2)=0=(x+1)^2+(y-3)^2=0x=-1y=3xy=-3
即(x²+4x+4)+(y²-6y+9)=0(x+2)²+(y-3)²=0所以x+2=0,y-3=0x=-2,y=3所以x-y=-5
x^2-2x+y^2+6y+10=0x^2-2x+1+y^2+6y+9=0(x-1)^2+(y+3)^2=0x-1=0,y+3=0x=1,y=-3(x-y)/(x+y)=4/(-2)=-2
x^2+y^2+2x-6y+10=0(x^2+2x+1)+(y^2-6y+9)=0(x+1)^2+(y-3)^2=0平方大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立所以两个都等于0所
x=1,y=-3再问:过程再答:化简一下就得到方程(x-1)2+(y+3)2=0.这里的2表示平方啊,不知道怎么打平方。很明显只有x=1,y=-3才满足啊。
x^2+3y^2-12y+12=0x^2+3(y-2)^2=0所以x^2=0,3(y-2)^2=0x=0,y-2=0y=2y^x=2^0=1
x²+2x+1+y²-6y+9=0(x+1)²+(y-3)²=0∴x+1=0y-3=0∴x=-1y=3
x²-2x+y²+6y+10=0(x²-2x+1)+(y²+6y+9)=0(x-1)²+(y+3)²=0∴x-1=0,y+3=0∴x=1,y
x^2+2x+y^2-6y+10=0整理已知式:(x^2-2x+1)+(y^2+6y+9)=0(x-1)^2+(y+3)^2=0因为任何数的平方都是非负数,所以此时:x-1与y+3只能同时等于零,才能
用x分之3加y分之4乘以(x+y),然后化简,再用均值不等式就出来了……(3/x+4/y)乘(x+y)等于7+3y/x+4x/y然后由于x,y大于0,所以用均值不等式即可……
原式=(x-3)^2+(y+1)^2=0所以x=3,y=-1所以3√(x*x-y*y)=3√(9-1)=2
由题意可得x²+y²+2x+6y+10=0(x+1)²+(y+3)²=0所以x=-1,y=-3
X²+y²一10X一12y+61=0(X²—10X+25)+(y²一12y+36)=0(X—5)²十(y—6)²=0(X一5)²=
x^+y^-8x-6y+25=0(x-4)^+(y-3)^=0x=4y=33x+4y=3*4+4*3=24^表示平方追问:怎么得出(x-4)^+(y-3)^=0回答:x^+y^-8x-6y+25=0x