1.y=2x^2+4X-7\x^2+2x+3 求定义域和值域

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 因式分解x(x+y)(x-y)-x(x+y)^2 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= *-----------------------------------------------*| 6 4 X | 8 X X | X X 5 || X X X | X X X | X 7 8 || X X X | X X X | X X X ||---------------+---------------+--------------- || X X X | X X X | 5 1 X || X X X | X 6 X | X X X || 8 X X | 3 5 X | 2 X X || (x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 (x-4y)(2x+y)= (x+y)(x^2+y^2)(x-y)(x^4+x^4)=? y=x^2-2x（x y=x^2+2x(x 3^x+2x=y,x 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 几道分式求值 速度 马上就要1. 1/x-y + 1/x+y + 2x/x^2+y^2 + 4x^3/x^4+y^4 + 8x^7/y^8-x^82. x-8/x-9 - x-7/x-8 - x-5/x-6 + x-4/x-53. 1/x^2+3x+2 + 1/x^2+5x+6 + 1/ x^2+4x+34. 1/x^2+2x-1 - 2/x^2+2x+1 + 1/ 化简(2x/(x+y)-4x/(y-x))/8x(x^2-y^2)得 1.(x-y)(x+y)+(x-y)+(x+y)2.x(x+2)-(x+1)(x-1),其中x=-二分之一请写清步骤,结果. 化简y(x+y)+(x+y)(x-y)-x^2 (2x-7)(x-1)+(2x-3)(2x+3) 2(x-8)(x-5)-(2x-1)(x+2) 3x(3y-x)-(4x-3y)(x+3y)(2-b)(3+b)-(2-b)(2+b)1.(2x-7)(x-1)+(2x-3)(2x+3) 2.2(x-8)(x-5)-(2x-1)(x+2) 3.3x(3y-x)-(4x-3y)(x+3y)