如果2x y 3=x 3y 5=1那么将原方程化为

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已知x+y=2,xy=-1,求x3次方y+2x平方y平方+xy3次方的值

x³y+2x²y²+xy³=xy(x²+2xy+y²)=xy(x+y)²=-1*2²=-4

已知x+y=5,x2+y2=13,求代数式x3y+2x2y2+xy3的值.

x3y+2x2y2+xy3=xy(x2+2xy+y2)=xy(x+y)2,∵x+y=5,∴(x+y)2=25,x2+y2+2xy=25,∵x2+y2=13,∴xy=6,∴xy(x+y)2=6×25=1

已知x-y=1,求代数式x4-xy3-x3y-3x2y+3xy2+y4.

原式=(x4-xy3)+(y4-x3y)+(3xy2-3x2y)=x(x3-y3)+y(y3-x3)+3xy(y-x)=(x3-y3)(x-y)-3xy(x-y)=(x-y)(x3-y3-3xy)=(

2y=-1+xy3(y的三次方),对x求导,答案是2y'=y的三次方+3x乘以y的2次方乘以y' 求解释,谢谢

两边分别求导,得(2y)'=(-1+xy^3)'2y'=(xy^3)'2y'=x'y^3+x(y^3)'(uv)'=u'v+uv'2y'=y^3+x*3y^2*y'2y'=y^3+3xy^2*y'

2y=-1+xy3(y的三次方),对x求导,答案是2y'=y的三次方+3x乘以y的2次方乘以y'

两边分别求导,得(2y)'=(-1+xy^3)'2y'=(xy^3)'2y'=x'y^3+x(y^3)'(uv)'=u'v+uv'2y'=y^3+x*3y^2*y'2y'=y^3+3xy^2*y'怎么

已知x+y=4,x2+y2=14,求x3y-2x2y2+xy3的值.

∵x+y=4,∴(x+y)2=16,∴x2+y2+2xy=16,而x2+y2=14,∴xy=1,∴x3y-2x2y2+xy3=xy(x2-2xy+y2)=14-2=12.

已知x-y=1/xy=3.求x3次方y-2x2y2+xy3

x3次方y-2x2y2+xy3=xy(x²-2xy+y²)=xy(x-y)²=3x3²=27如果本题有什么不明白可以追问,再问:=xy(x2-2xy+y2)=x

若x+y=-1,则x4+5x3y+x2y+8x2y2+xy2+5xy3+y4的值等于(  )

原式=x4+x3y+4x3y+x2y+4x2y2+4x2y2+xy2+4xy3+xy3+y4,=x3(x+y)+4x2y(x+y)+xy(x+y)+4xy2(x+y)+y3(x+y),=-x3-4x2

若x+y=1则代数式x4+6x3y—2x2y+10x2y2—2xy2+6xy3+y4的值等于_____

原式=(x^4-2x²y²+y^4)+6xy(x²+2xy+y²)-2xy(x+y)=(x²-y²)²+6xy(x+y)²

已知x+y=5,xy=3,求代数式x3y-2x平方y平方+xy3

已知x+y=5,xy=3,代数式x3y-2x平方y平方+xy3=xy(x²-2xy+y²)=xy(x-y)²=3×[(x+y)²-4xy]=3×(25-12)=

已知:| x + y + 1| +| xy - 3 | = 0,求代数式xy3 + x3y 的值.

∵|x+y+1|≥0,|xy-3|≥0|x+y+1|+|xy-3|=0,∴x+y+1=0,即x+y=-1xy=3xy3+x3y=xy(x²+y²)=yx[(x+y)²-2

若x-y=6,xy=17/36,则代数式X3y-2x2y2=xy3的值为__ X后面的数字为X的平方

应该是X3y-2x2y2+xy3原式=x3y-2x2y2+xy3=xy(x2-2xy+y2)=xy(x-y)2=17/36*6=17麻烦采纳,谢谢!

已知x+y=4,xy=2,则x3y+x2y2+xy3的值:

x+y=4,xy=2后者平方后二式相加再加后者平方

已知x=√3-√2,y=√3+√2,求x3y+xy3

x3y+xy3=xy(x^2+y^2)=(√3-√2)(√3+√2)((√3-√2)^2)+(√3-√2)^2)=1*(3-2√6+2+3+2√6+2)=10

已知x-y=l,xy=2,求x3y-2x2y2+xy3的值.

∵x-y=l,xy=2,∴x3y-2x2y2+xy3=xy(x2-2xy+y2)=xy(x-y)2=2×1=2.

当x-y=1时,那么x4-xy3-x3y-3x2y+3xy2+y4的值是(  )

x4-xy3-x3y-3x2y+3xy2+y4=(x4-xy3)+(y4-x3y)+(3xy2-3x2y)=x(x3-y3)+y(y3-x3)+3xy(y-x)=(x3-y3)(x-y)-3xy(x-

已知x=根号7+根号3,y=根号7-根号3 求:x3+y+xy3+2的值

错了吧,x³+y是x³yx+y=2√7xy平方差=7-3=4则(x+y)²=x²+2xy+y²=(2√7)²x²+y²=