-1<=Y<1,看成两个不等式,分开算就是了,加油哈!
3x+y=2y=2-3x-1<=2-3x<5-3<=-3x<31>x>-1将就着报对!
得出:Y=2-3X又因为:-1<=Y<5即:-1<=2-3X<5得出:-3<=-3x<3所以:X>1或X<=-1