x^2 2y^2 2xy-4y 4=0
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1.ax-2ay+2bx-4by=ax+2bx-(2ay+4by)=(x-2y)(a+2b)2.x^3+x^2-4x-4=x(x^2-4)+(x^2-4)=(x-1)(x-2)(x+2)3.x^2-x
x2y+xy2=xy(x+y)=66,设xy=m,x+y=n,由xy+x+y=17,得到m+n=17,由xy(x+y)=66,得到mn=66,∴m=6,n=11或m=11,n=6(舍去),∴xy=m=
原式分解因式得x^3y^3(2x-y)=(xy)^3(2x-y)=8/3.(x^3表示x的3次方)
4y4,y,4xy,3x²y,3x3次方
1、x+y=a,xy=b①x²+y²=x²+2xy+y²-2xy=(x+y)²-2xy=a²-2b②x³+y³=(x
原方程组可化为4x-3y=12 ①3x-4y=2 ②,①×4-②×3,得7x=42,解得x=6.把x=6代入①,得y=4.所以方程组的解为x=6y=4.
∵x+y=6,xy=4,∴(1)x2+y2=(x+y)2-2xy,=62-2×4,=28;(2)(x-y)2=x2+y2-2xy,=28-2×4,=20;(3)x4+y4=(x2+y2)2-2x2y2
等式xy+2lnx=y4两边直接对x求导,得y+xy′+2x=4y3y′将x=1,y=1代入上式,有 y'(1)=1 故过点(1,1)处的切线方程为y-1=1•(x-1),即x-y
(x⁴+y⁴)÷(xy)²=[(x²+y²)²-2x²y²]/(x²y²)=[(4xy)
解(15x^4y^4-9x^5y³-3x^6y²)/(-3x²y)²=(15x^4y^4-9x^5y³-3x^6y²)/(3x²y
(x+y+z)^2=[(x+y)+z]^2=(x^2+2xy+y^2)+z^2+2zx+2zy=x^2+y^2+z^2+2xy+2xz+2yz=x^2+y^2+z^2+2(xy+xz+yz)=0x+y
∵x+y=a∴x2+y2+2xy=a2又∵x2+y2=b2∴2xy=a2-b2x4+y4=(x2+y2)2-2x2y2=(x2+y2)2-(2xy)22=b4−(a2−b2)22=-12a4+a2b2
20x2+253x+800=(5X+32)(4X+25)(x+y)²=(x+y)²(x+y)²=(x²+y²+2xy)²=(x²+
由已知,得x=1y,∴1x4+14y4=1x4+x44=(1x2-x22)2+1,当1x2=x22,即x=42时,1x4+14y4的值最小,最小值为1.故选C.
x2+y2=(x+y)2-2xy=14x3+y3=(x2+y2)×(x+y)-xy2-yx2=14×4-xy(x+y)=52……剩下的就是这么个算法,手机党,求个最佳哈
方程ax^2+bx+c=0,判断这个方程有没有实数根,有几个实数根,就要用ΔΔ=b^2-4ac若Δ<0,则方程没有实数根Δ=0,则方程有两个相等实数根,也即只有一个实数根Δ>0,则方程有两个不相等的实
1)2x³y—4x平方y平方+2xy³=2xy(x²-2xy+y²)=2xy(x-y)²2)x4次方—2x平方y平方+y4次方=(x²-y&
xy³-x³y²-8x²y-y4
X^2+y^2=(x+y)^2-2Xy=a^2-2bx3次方+y3次方=(x+y)(X^2+y^2-xy)=a(a^2-2b-b)=a^3-3abx4次方+y4次方=(x^2+y^2)^2-2x^2y
因为x²+4y²+x²y²-6xy+1=0(x²-4xy+4y²)+(x²y²-2xy+1)=0(x-2y)²