The factors of (x4 - 7x2y2 + y4) are(a) (x2 + y2 - 3xy)(x2 + y2 + 3xy)

1.	The factors of (x4 - 7x2y2 + y4) are(a) (x2 + y2 - 3xy)(x2 + y2 + 3xy)(b) (x2 - y2 + 3xy)(x2 + y2 - 3xy)(c) (x2- 3xy + y2)(x2 - 3xy - y2)(d) (x2 + 3xy + y2)(x2 - 3xy - y2)
Answer» (a) (x² + y² +3xy)(x² + y² - 3xy) x⁴ - 7x²y² + y⁴ = x⁴ + 2x²y² + y⁴ - 9x²y² = (x² + y²)² - (3xy)² = (x² + y² +3xy)(x² + y² - 3xy)

The factors of (x4 - 7x2y2 + y4) are(a) (x2 + y2 - 3xy)(x2 + y2 + 3xy)(b) (x2 - y2 + 3xy)(x2 + y2 - 3xy)(c) (x2- 3xy + y2)(x2 - 3xy - y2)(d) (x2 + 3xy + y2)(x2 - 3xy - y2)

Answer»

(a) (x² + y² +3xy)(x² + y² - 3xy)

x⁴ - 7x²y² + y⁴

= x⁴ + 2x²y² + y⁴ - 9x²y²

= (x² + y²)² - (3xy)²

= (x² + y² +3xy)(x² + y² - 3xy)