5x+10=5y 4x+4y=8要求x、y 2.结算：（2x-3y)^2-(y+3x)(3x-y) 利用乘法公式计算和分解因式

5x+10=5y 4x+4y=8要求x、y 2.结算：（2x-3y)^2-(y+3x)(3x-y) 利用乘法公式计算和分解因式 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 5x-4y(y-x)=? 3(2X+Y)+(2(2x-Y)=6 (8X+4y)-(10X-5Y)=2 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? y=|-x.x+4x+5| （5x+3y)(3y-5x)-(4x-y)(4y+x)= x*x+2x+y*y-4y+5=0 x= y= 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 x+y／y=5／4,则x／y=---------------- 已知：4x = 5y,求(x+y) ：y 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? x-y+5x-4x= ?x-y+5x-4x= ?