y=2x-4/x-3 (x>3 )则2x+y 最小值为多少y=2x-4/x-3(x>3 )则2x+y最小值为多少

若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 若2x=3y,则(x*x+y*y)/x*x=? 3^x+2x=y,x 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x x(x-y)2-(y-x)3 2x-y/x+y=4,则4x-2y/2x+2y+3x+3y/2x-y 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（） 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2