6x^2-5xy-6y^2-2x-23y-20-搜答案-搜搜做题作业网

xy=6,x-y=5,x^2y+xy^2

(x+y)"=(x-y)"+4xy=25+24=49x+y=±7x"y+xy"=xy(x+y)=±42

x^2-xy-6y^2+3xy+y+2

3xy是3x原式=(x-3y)(x+2y)+3x+y+2十字相乘x-3y2×x+2y1所以原式=(x-3y+2)(x+2y+1)

1.x^4+5x^2-6=(x^2+6)(x^2-1)=(x^2+6)(x-1)(x+1)2.(x+y)(x+y+2xy)+(xy+1)(xy-1)=(x+y)^2+2xy(x+y)+(xy+1)(x

x-5xy+6y=0(√x-2√y)(√x-3√y)=0所以√x=2√y,√x=3√yx=4y或x=9y原式=(8y)/(9y)=8/9或=(14y)/(20y)=7/10

Solution:x^2-2xy+3y^2=9(1)4x^2-5xy+6y^2=30(2)Eq(1)*5-Eq(2)*2,wehavex^2-y^2=5(3)Eq(2)-Eq(1),wegetx^2+

x=-1,y=-6或x=6,y=1代入式子得x^2-xy^2=37或30x^2y+xy^2=-42或42

（-XY/2）（2X²Y/3-3XY²/2+6Y/5）=-X³Y²/3+3X²Y³/4-3XY²/5

原式=(5x²-15x)-(2xy-6y)=5x(x-3)-2y(x-3)=(x-3)(5x-2y)

是不是x-5√xy-6y=0?(√x-6√y)(√x+√y)=0x>0,y>0则√x+√y>0所以√x-6√y=0√x=6√yx=36y所以√xy=6y所以原式=(36y-12y+y)/(36y+6y

已知x-y=6,xy=-2,求3（xy+x-2y）-5(y-2x)+2(xy-x)的值.=3xy+3x-6y-5y+10x+2xy-2x=5xy+11x-11y=5×(-2)+11×6=-10+66=

(5xy+4x+7y)+(6x-3xy)-(4xy-3y)=5xy+4x+7y+6x-3xy-4xy+3y=(5xy-3xy-4xy)+(4x+6x)+(7y+3y)=-2xy+10x+10y=-2x

xy/x+y=6∴xy=6(x+y)3x-2xy+3y/-x+3xy-y=[3x-12(x+y)+3y]/[-x+18(x+y)-y]=-9(x+y)/17(x+y)=-9/17再问：你在啊？再答：在

√x(√x+2√y)=√y(6√x+5√y)(√x)²-4√(xy)-5(√y)²=0(√x-5√y)(√x+√y)=0∴√x=5√y√x=-√y舍去原式=[(√x)²-

[(x-y)/(x+3y)]/[(x^2-y^2)/(x^2+6xy+9y^2)]-xy/(x+y)=(x-y)/(x+3y)*(x+3y)^2/(x-y)(x+y)-xy/(x+y)=(x+3y)/

因为√x(√x+2√y)=√y(6√x+5√y),所以x+2√(xy)=6√(xy)+5y,所以x-4√(xy)-5y=0,所以(√x+√y)(√x-5√y)=0,所以√x+√y=0或√x-5√y=0

6x^2y^2+xy-15

6x²y²+xy-15=(2xy-3)(3xy+5)

1、(-7x^y)(2x^y-3xy^3+xy)=-14x^(2y)+21x^(y+1)y^3-7x^(y+1)y;2、((x-y)^6)/((y-x)^3)/(x-y)=-(x-y)^3/(x-y)

x²-xy+3y-3x=x(x-y)-3(x-y)=(x-y)(x-3)2x²+xy-y²-4x+5y-6=(2x-y)(x+y)-4x+5y-6=(2x-y+2)(x+

原式=-x²y+2xy²+2x²y²-4xy³-3x³+27x³y-18x²y²+2x²y-18x&

x^2y+xy^2＝xy×（x+y）＝6×5＝30