若实数x,y满足{x-y+1≤0,x>0,y≤2},则y/x的取值范围是答案是[2,正无穷] 我想知道为什么会是正无穷?

若实数x,y满足x-y+1》=0,x+y>=0,x 若实数x,y满足x-y+1>=0,x+y>=0,x 若实数x,y满足约束条件x-y≥0,x+y≥0,2x+y≤1,则y/(x+1)的最大值是多少, 实数x,y满足{x-y+1>=0;y+1>=0;x+y+1 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 若实数x,y满足x-4y+3≤0,3x+5y-25≤0,x≥1,则2x-y的最大值是多少 若实数x,y满足{x-y+1≥,x>0},则y/(x-1)的取值范围是 若实数x满足条件x>=0,y 若实数x,y满足不等式组x>=0 ,y>=0,x+2y 若实数x,y满足x^2-xy-y^2 =0,则x/y=? 己知实数x,y满足{ (x-y+6) (x+y-6)>=0,1 已知实数x,y满足x-ay-1>=0,2x+y>=0,x 若实数x,y满足{x-y+1≤0 x>0 x≤2 } 则y/x的取值范围是 已知实数x,y满足{x=>0,y 已知实数x,y满足{x=>0,y 已知实数x,y满足不等式组x≥0,y≥0,x+y≤1,则x^2+y^2-2x-2y的最小值 若实数x,y满足不等式组｛x+y≥2 ｛2x-y≤4 ｛x-y≥0 ,则2x+3y的最小值是? 若实数X,Y满足X²+Y²+4X-2Y +1=0,则X²-6X+Y²-2Y的最大值是多少