已知x y=-3,x的三次方加y的三次方等于-18求x的七次方加y的七次方-搜答案-智慧作业帮

A-B=x³+2y³-xy²-(-y³+x³+2xy²)=x³+2y³-xy²+y³-x³

已知x+y=1,则x^3+y^3+3xy=（x+y）(x^2-xy+y^2)+3xy=1×(x^2-xy+y^2)+3xy=x^2-xy+y^2+3xy=x^2+2xy+y^2=(x+y)^2=1^2

/>根据非负数之和为0得x+1=02(y-2）=0解得x=-1y=2于是x³-3xy+y³=-1³-3×(-1)×2+2³=-1+6+8=13

见图

x^3y-2x^2y^2+xy^3=x^3y+2x^2y^2+xy^3-4x^2y^2=xy(x^2+2xy+y^2)-4x^2y^2=xy(x+y)^2-4x^2y^2=12×7×7-4×12×12

X2+Y2-4X-6Y+13=0X2-4X+4+Y2-6Y+9=0（X2-4X+4）+（Y2-6Y+9）=0（x-2）2 +（y-3）2=0所以,x-2=0 x=2y-

已知x=4/5,y=-1/5,求x三次方-y的三次方+3x平方y-3xy的平方x三次方-y的三次方+3x平方y-3xy的平方=(x-y)³=[4/5-(-1/5)]³=(4/5+1

x³y+2x²y²+xy³=xy(x²+2xy+y²)=xy(x+y)²=1×3²=9

已知A=x³+2y³-xy²,B=-y³+x³+2xy²,其中x等于1\3,y等于2A-B=（x³+2y³-xy

已知x+y=1,则x^3+y^3+3xy=（x+y）(x^2-xy+y^2)+3xy=1×(x^2-xy+y^2)+3xy=x^2-xy+y^2+3xy=x^2+2xy+y^2=(x+y)^2=1^2

x的三次方y的平方+x的平方y三次方=x²y²(x+y)=(xy)²(x+y)=(-2)²*(-3)=-12

-xy(x²y的五次方-xy的三次方-y)=-x³y的6次方+x²y的4次方+xy²=-（xy²）³+（xy²）²+xy

由题可知,x+y+1=0,xy+3=0即得x+y=-1,xy=-3（x+y)²=x²+2xy+y²∴(-1)²=x²+2×（-3）+y²即x

原式等于(xy)^2(x+y)将x+y=2,xy=4代入,得原式等于16×2=32

解x-y=5两边平方x²-2xy+y²=25∵xy=3∴x²+y²=25+2xy=25+6=31∴x³y+xy³=xy(x²+y&

x的三次方y-xy的三次方=xy(x²-y²)=xy(x+y)(x-y)=-3x0x(x-y)=0如果本题有什么不明白可以追问,如有其它问题,请谅解,

x³-y³-x²y+xy²=(x³-y³)-(x²y-xy²)=(x-y)(x²+xy+y²)-xy