若y=(1/3)x-2,则(1/3)x*x-2xy+3y*y-2的值是?

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） 若y=x(x-1)(x-2)(x-3),则y′（0）= 若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y= 若x,y满足|x-y+1|+(x+y+3)^2=0则x^2-y^2= 若变量x,y满足约束条件{x>=-1;y>=x;3x+2y 若(5x+y)(7x+10y)=1/2,则x/y=______;若x+1/x=3,则x^2+1/x^2 若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值? 若X+6=Y-X-8=2X-3Y-1,则3X-Y=? 若X+6=Y-X-8=2X-3Y-1,则3X-Y=? 若2X+3Y-1=Y-X-8=X+6则2X+Y= 若2X+3y-1=y-x-8=x+6,则2x-y=? 若x+6=y+x-8=2x-3y-1,则x-y= 若2x=3y,则(x*x+y*y)/x*x=? (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)