(1):(2X-Y-3)^2 (2):59.8*60.2 (3）198^2 （4）：4(X+1)^2-（2x+5）（2X-5）第1,2,3,4题要整式计算

(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 化简:5(x-y)+2(x+y)-3(x-y) 绝对值化简|x-y+1|-2|y-x-3|+|y-x|+5y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (2x-3y)-(5x-y) (2X-3y)-(5x-y) (2x-5y)(3x+y) 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1 （2x+y-1)(2x-y+1)-(3x+y)(3x-y),其中x=5分之1, x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² {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+2y)(x-2y)-(2x-y)^2+(3x-y))2x-5y)]/(-x)我急用