2020 · Q23
If the area of a square is 2401x⁴ + 196x² + 4, then what is its side length?
Elementary MathematicsAlgebra
- A49x² + 3x + 2
- B49x² - 3x + 2
- C49x² + 2
- D59x² + 2
Explanation
2401x⁴ + 196x² + 4 = (49x²)² + 2·49x²·2 + 2² = (49x² + 2)². A square of area (49x² + 2)² has side 49x² + 2. Expanding (49x² + 2)² recovers the original quartic, confirming the factorisation.