y =( 1/2)x- 1(x & gt; =2)
y = 1-( 1/2)x(x & lt; 2) Point (x, y) above
Similarly, set b also consists of two dotted lines:
y =-x+b(x & gt; =0)
y = x+b(x & lt; Points below 0 (x, y)
If their intersection is not an empty set, b>= 1 will do.
(2) x+2y
So as long as b=9/2, the meaning of the problem can be satisfied.
Drawing pictures by yourself can help you understand.