Answer:
16
Step-by-step explanation:
|x - 16| less than/equal to 4
Means x can be between;
-4+16 and 4+16, i.e [12,20]
|y - 6| less than/equal to 2
Means x can be between,
-2+6 and 2+6, i.e [4,8]
x - y would be greatest when x is greatest and y is least:
20 - 4 = 16