2018 · Q7
If 65x - 33y = 97 and 33x - 65y = 1, then what is xy equal to?
Elementary MathematicsAlgebra
- A2
- B3
- C-2
- D-3
Explanation
Adding the two equations: 98x − 98y = 98, so x − y = 1. Subtracting them: 32x + 32y = 96, so x + y = 3. Solving gives x = 2 and y = 1, hence xy = 2, option (A).