灵鹊做题网3x^2-y^2=8,x^2 xy y^2=4
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(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=4x-2y-z-5x[6y-(x+y)]+x-(3y-10z)=4x-2y-z-30xy+5x²+5xy+x-3
设a=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)那么y=a*(x-10);那么y^=a^*(x-10)+a*(x-10)^=a^*(x-10)+a那么y
解13x-2y=9x-3y=2将式2左右两边同时乘以3得3x-9y=6与式1相减有-9y+2y=6-9解得y=3/7代入代2有x-3*3/7=2解得x=23/7故x=23/7y=3/7解2x+y=5x
根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),根据二次根式有意义得：X+Y-8≥0,8-X-Y≥0,∴X+Y≥8,X+Y≤8,∴X+Y=8,左边为0,右边两个非负
这样算,分离变量:x²+x=(x+1)²-(x+1)然后,除下来,就等于x+1-1=x注意,x≠-1!
3x^2(x-y)+6x(y-x)=3x^2(x-y)-6x(x-y)=(x-y)(3x^2-6x)=3x(x-y)(x-2)
3x=8yx/y=8/3（1）x+y/y=x/y+1=8/3+1=11/3(2)2x+3y/x-2y分子分母同时除以y得=(2x/y+3)/(x/y-2)=(16/3+3)/(8/3-2)=(25/3
1)x(x-y)(x+y)-x(x+y)^2=x((x-y)(x+y)-(x+y)^2)=x(x^2-y^2-x^2-2xy-y^2)=x(-2xy-2y^2)=-2xy(x+y)2)（2a+b)(2
X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1
因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6
2x+3y-1=y-x-8y-x-8=x+6这是一个二元一次方程组解得：3x+2y=-72x-y=-14解得x=-5y=4所以2x+3y-1=y-x-8=x+6,则x=-5
这问题也来问,帮你算了一下X=2/3y=4/3
先一个一个的展开括号项,再同项合并就行了啊[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x=[xx-xy-(xy-yy)+x(x-y)+y(x-y)]÷2x=[xx-xy-xy+yy+xx-
y=3/(x+1/x+1)x+1/x≤-2,所以x+1/x+1≤-1令t=x+1/x+1,则t≤-1,y=3/t值域为[-3,0)再问：你写的我看不大懂再问：一步步写再答：
解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy
解代数式得：-3x的平方y-2y的三次方因为1/2的平方=-1/2的平方,所以结果仍正确给分吧!嘿嘿!
原式可以化为：y*x^2+(y-3)*x+1=0Δ=(y-3)^2-4y≥0解得y≥9或y≤1由于x
解9y=3x-(x-1)2x-9y+1=0①4(x+y)-(2x+4)=8y2x-4y-4=0②②-①得：5y-5=0∴y=1将y=1代入①得：2x-9+1=0∴x=4∴方程的解为：x=4,y=1