B).
the area of the overall rectangle is ab, but you need to subtract the 4 smaller squares. each square is x^2, and there are 4 of them.
this is how they get ab-4x^2
10^1=10
10x0.23=final answer=2.3
the answer would be 119.3 miles
That would be the definition of a numerical expression.
An algebraic expression, on the other hand, would have variables.