If a - b = 3 and a^2 + b^2 = 33, find the value of ab.	Choose the most appropriate option
A) 12
B) 15
C) 10
D) 18
E) 13

Rationale: "2 ab = ( a ^ 2 + b ^ 2 ) - ( a - b ) ^ 2 = 33 - 9 = 24 ab = 12 . answer is a ."
Answer: A