Question

5. Factories by using identities
(a)64m3-343n3
(b)4y2-4y+1​

Answer 1

(a) [Using x³ - y³ = (x - y) (x² + xy + y²)

=> 64m³ - 343n³

=> 64m³ - 343n³ = (4m)³ - (7n)³

=> (4m - 7n) {(4m)² + (4m)(7n) + (7n)²}

=> (4m - 7n) (16m² + 28mn + 49n²)

(b) [Using a² – 2ab + b² = (a – b)²]

=> 4y² – 4y + 1

=> (2y)² – 2(2y) (1) + (1)²

=> (2y – 1)2

=> (2y – 1) (2y – 1)