The first picture represents the elements in B that are not (also) in A. So, we want the set difference of B and A:

For the second picture, we can work like this: if we take all the elements belonging to A, we only need to add the bottom-right part, which is the intersection of B and C. So, we can express the blue part as

E, because he is stealing everything, meaning he has a net profit. So, you would add everything. Since he 280 $1 bills, he just stole $280 which is a definite quantity, so we don't need a variable for it. Since everything else are indefinite quantities, we need variables (x, y, z). But, yeah, E should be the answer.
Answer:
20-15z
Step-by-step explanation:
-1+21-15z
20-15z
Subtract 5x from both sides
0=-30x
Divide both sides by -30
0=x
Final answer: x=0
Hope this helps!