Đáp án:`+`Giải thích các bước giải:

 ` b) (2x)/5 + (3-2x)/3 >= (3x+2)/2`

`<=> (12x)/30 + (30-20x)/30 >= (45x + 30)/30`

`=> 12x + 30 -20x >= 45x +30`

`<=>` `12x -20x - 45x>= -30 +30`

`<=>` `-53x >=0`

`<=>` `x<=0`

Vậy .

 `c) { ((x+2)(y+1) = xy+7),((x+1)(y-1) =xy):}`

`<=>` `{(xy+x+2y+2=xy +7),(xy-x+y-1=xy):}`

`<=>` `{(xy-xy+x+2y=7-2),(xy-xy-x+y=1):}`

`<=>` `{(x+2y=5),(-x+y=1):}`

`<=>` `{(3y=6),(-x+y=1):}`

`<=>` ` {(y=2),(-x+2=1):}`

`<=>` `{(y=2),(x=-1):}`

Vậy .