If a - b = 3 and a(power 2) + b(power 2) = 29, find the value of ab.  Choose the correct choice from the following answers:
A) 5
B) 8
C) 4
D) 10
E) 3

Rationale: "2 ab = ( a ( power 2 ) + b ( power 2 ) - ( a - b ) ( power 2 ) = 29 - 9 = 20 ab = 10 . answer is d ."
Answer: D