Question

solve the following . ​

Answer 1

Question :

• Evaluate ( x - 2y )² + ( 2x - y )²

Solution :

➨ ( x - 2y )² + ( 2x - y )²

➨ [ ( x )² - 2 * x * 2y + ( 2y )² ] + [ ( 2x )² - 2 * 2x * y + ( y )² ]

➨ [ x² - 4xy + 4y² ] + [ 4x² - 4xy + y² ]

➨ x² - 4xy + 4y² + 4x² - 4xy + y²

➨ x² + 4x² - 4xy - 4xy + 4y² + y²

➨ 5x² + 5y²

Identity used :

➨ ( a - b )² = a² - 2ab + b²