Here is a basic inequality question for which I cannot understand the answer:
If $$-1<a-b<10 ,and -3\le b\le1$$ then what inequality represents the range of values of a2?
I plug-in -3 and 1 for b for boundaries and get -4<a<11.
Since the boundary is for a2, the range would be 16<a2<121.
But...