For how many unique pairs of nonnegative integers {a, b} is the equation a^2 - b^2 = 25 true?  Choose the correct choice from the following answers
A) 1	B) 3	C) 5	D) 2	E) 9
Answer 2   (a+b)(a-b)=25   5cases For (a+b), (a-b)   25, 1   5, 5   Answer 2
<result>D</result>
For how many unique pairs of nonnegative integers {a, b} is the equation a^2 - b^2 = 25 true?