1 6x-4y-1 6x﹢4y-搜答案-搜搜做题作业网

x*x+y*y-4x+6y+13=0(x^2-4x+4)+(y^2+6y+9)=0(x-2)^2+(y+3)^2=0x-2=0,y+3=0x=2,y=-3

x*x+4y*y+2x*x-4y+2=0应该是x*x+4y*y+2x-4y+2=0可变换为（x+1)^2+(2y-1)^2=0x=-1,y=1/2,剩下的自己做一下,关键是上面一步要会

(2x-y)²-4(x-y)(x+2y)

x(x-y)+4(y-x)=x(x-y)-4(x-y)=(x-y)(x-4)=(x-y)(X+2)(X-2)

(x^2-y^2)/(x+y)-(4x(x-y)+y^2)/(2x-y)=(x-y)(x+y)/(x+y)-(4x^2-4xy+y^2)/(2x-y)=(x-y)-(2x-y)^2/(2x-y)=(x

x^4-16y^4

x^4-16y^4=(x^2+4y^2)*(x^2-4y^2)=(x^2+4y^2)*(x+2y)*(x-2y)

4(x+y)(x-y)^3-9(x+y)^3(x-y)=(x＋y)(x－y)[4(x－y)²－9(x＋y)²]=(x＋y)(x－y){[2(x－y)]²－[3(x＋y)]

16（x-y）（x-y）-25（x+y）（x+y)=[4(x－y)]²－[5(x＋y)]²=(4x－4y＋5x＋5y)(4x－4y－5x－5y)=(9x＋y)(﹣x－9y)=﹣(9

第一个两边乘128(x-y)-3(x+y)=-128x-8y-3x-3y=-125x-11y=-12(1)第二个6x+6y-8x+4y=16-2x+10y=16x-5y=-8(2)(1)-(2)×55

5(X-3Y)-6=2X+1,5x-15y-6=2x+13x-15y=7（1）3(X+Y)=4(2X-Y)+163x+3y=8x-4y+165x-7y=-16（2）（1）×5-（2）×3得15x-75

(2x-y)^2-4(x-y)(x+2y)

4x^2+y^2-4xy-4(x^2-xy+2xy-2y^2)展开化简吧!

∵(y-3)/(x-1)=2,x≠1,可化为y-2x=1,∵A∩B=空集,∴y-2x=1方程组无解ay+4x=16∴1/a=-2/4≠1/16解得a=-2又x≠1,则y≠3,∴3a+4≠16,a≠4当

2(x-y)/3-x+y/4=-1（1）6(x+y)-4(2x-y)=16（2）（1）方程两边同乘以12得8（x-y）-3(x+y)=-12合并同类项得5x-11y+12=0(3)(2)合并同类项得1

(x+y)(x+y-6)+9=(x+y)^2-6(x+y)+9=((x+y)-3)^2=(x+y-3)^2x²-16y²-x-4y=(x+4y)(x-4y)-(x+4y)=(x+4

[(5x+3y)^2-(3y+x)(3y-x)^16]/(4x)=【25x^2+30xy+9y^2-9y^2+x^2]/4x=(26x^2+30xy)/4x=13x/2+15y/2=13/2-15/2

(2x-y)²-4(x-y)(x+y)=(4x²-4xy+y²)-4(x²-y²)=4x²-4xy+y²-4x²+4y&

x=-1,y=2

这慢慢做不就好了,这么简单的式子

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