解：根据题意由题意：-1<=x+y<=1 (1)1<=x-y<=3 (2)不等式(2)乘以2得到：2<=2x-2y<=6 (3)将不等式(1)与(3)相加得到：1<=3x-y<=7.即 3x-y 的取值范围是 1<=3x-y<=7.好评，，O(∩_∩)O谢谢
