2019 · Q90
How many pairs of natural numbers are there such that the difference of their squares is 35?
Elementary MathematicsNumber System
- A1
- B2
- C3
- D4
Explanation
a^2-b^2 = (a-b)(a+b) = 35 = 1x35 = 5x7. (a-b,a+b) = (1,35) gives (18,17); (5,7) gives (6,1). Two pairs.