|x-y 3| (x-y 2013²)=0
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x³(a+1)-xy(x-y)(a-b)+y³(b+1)=x³(a-b+b+1)-xy(x-y)(a-b)+y³(b+1)=x³(a-b)+x
∵y=-2/x在(负无穷,0)上是增函数∴当y1>y2>y3>0时,0>x1>x2>x3选C
x3+y3=100(x+y)(x^2-xy+y^2)=100因x+y=1所以x^2-xy+y^2=100(x+y)^2-3xy=1001-3xy=100xy=-33x^2+y^2=(x+y)^2-2x
因为√(1-y)有意义,所以1-y≥0,所以(y-1)√(1-y)=-(1-y)√(1-y)=-√(1-y)³所以原式成为,√(x+1)+√(1-y)³=0,所以√(x+1)=0,
解题思路:(1)应该分成两段来表示其费用,一是4千米以内的费用,二是4千米至15千米之间的费用,两者相加即可;(2)设其行驶了x千米,根据不同的收费标准表示各段的费用,然后根据总价格列方程,解方程即可
原方程组可化简为y=36−5x(1)−x+5y=24(2),把(1)代入(2)得:-26x+180=24,26x=156,即x=6,把x=6代入(1)得:y=6.所以方程组的解为x=6y=6.
3x(M-5x)=3xM-15x²=6x²y³+n3xM=6x²y³-15x²=NM=2xy³MN=-30x³y
x4+y2x2+y4=x^4+2y^2x^2+y^4-x^2y^2=(x^2+y^2)^2--x^2y^2=(x^2+y^2+xy)(x^2+y^2-xy)x3+x2y-xy2-y3=(x-y)(x^
(x+y+z)^3-x^3-y^3-z^3=3yx^2+3xy^2+3xz^2+3yz^2+3zx^2+3zy^2+6xyz=3xy(x+y)+3z^2(x+y)+3z(x^2+y^2+2xy)=3x
如果你的X2是x的平方,X3是x的三次方那么答案是:-(x-y+z)*(x-y-z)*(x+y-z)
(x+y)³=x³+y³+3x²y+3xy².记忆方法:各立方,然后3x方y,3xy方(x+y)³=x³-y³-3x
是求(-x)^2009+y^3这个吧∵(x-1)2≥0|2x+y|≥0(x-1)2与|2x+y|互为相反数∴x-1=02x+y=0∴x=1,y=-2∴(-x)^2009+y^3=(-1)^2009+(
由于x<-1,y>0,∴根(x+1)²=|x+1|=-(x+1).根y³=y根y.所以原式=-(x+1)/y根y=-(x+1)根y/y².
^3代表3次方,^2代表平方X^3+X^2-Y^3-Y^2=(x^3-y^3)+(x^2-y^2)=(x-y)(x^2+xy+y^2)+(x-y)(x+y)=(x-y)(x^2+xy+y^2+x+y)
x3(y-z)+y3(z-x)+z3(x-y)=x3(y-z)+y3(z-x)-z3(y-z)-z3(z-x)=(x3-z3)(y-z)+(y3-z3)(z-x)=(x-z)(y-z)(x2+xz+z
27.已知x=1.25,y=-0.64时,求[(x+y)3-(x3+y3)]÷(x+y)的值.[(x+y)^33-(x^3+y^3)]÷(x+y)解,得:==(x+y)^3*1/(x+y)-(x+y)
x^3+y^3+z^3+(x+y)^3+(y+z)^3+(z+x)^3=[x^3+(y+z)^3]+[y^3+(z+x)^3]+[z^3+(x+y)^3]=(x+y+z)(x^2-xy+y^2-xz+
y=(1-C1-C2)y1(x)+C1y2(x)+C2y3(x)即y=y1(x)+C1*[y2(x)-y1(x)]+C2*[y3(x)-y1(x)]而y1(x),y2(x),y3(x)都是线性方程y'
x3+3xy-y3=(x-y)(x^2+y^2+xy)+3xy=-x^2-y^2+2xy=-(x-y)^2=-1