若2x^2-3x+1+y=0,则x+y的最大值

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若|x+y+1|+(x-2y)的平方=0,则x+2y=? 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(2x-y-1)2+|x-2y-3|=0,求代数式(2x+y)(2x-y)-(x+2y)(x-2y-1)的值若(2x-y-1)²+|x-2y-3|=0,求代数式(2x+y)(2x-y)-(x+2y)(x-2y-1)的值 若实数X,Y满足{ x-y-1≤0,x+y-3≤0,x≥1,则函数z=2x-y的最大值 若变量x y满足约束条件x+y≤5 x-y≤-1 x≥0 则z=3x-2y的最小值 若2x^2-3x+1+y=0,则x+y的最大值 若根号x+y-1+(y+3)^2=0,则x+y的平方根是? 已知x属于R,y>0,集合A={x|x*x+x+1,-x,-x-1},集合B={-y,-y/2,y+1}若A=B,则x*x+y*y的值为 若y=x(x-1)(x-2)(x-3),则y′（0）= 若|2x-y+5|+(x+2y-4)的平方=0,则（2x-y)的三次方-（x-3y)(y-2x)的平方 若x+2y分之x-y=3,则代数式x+2y分之2（x-y)-3(x-y)分之x+2y的值为 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 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*x+y*y=x+y-1/2,求x,y的值如题