y=(4x^2-7)(2-x)

(x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (x-4y)(2x+y)= 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 2x+y=90 y：x=4:7 {x y=4,2x 3y=7 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y (x+y)(x^2+y^2)(x-y)(x^4+x^4)=? 把(x-y)看做一个整体,合并同类项5(x-y)+2(x-y)-4(x-y)=3(x-y)次方-4(x-y)+7(x-y)-6(x-y)次方= y=4x^2-5x+7/x-2(x>2),求y最值 初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x x+y=2,x^3+y^3=14,求x^4+y^4,x^7+y^7 方程2分之x+y+2分之x-y=7,4(x+y)-5(x-y)=2