Question

Factorize - 7(3x-4y)²-28(2x-y)²​

Answer 1

Answer:

$7(3x - 4y)^{2} - 28 {(2x - y)}^{2}$

$= 7(9 {x}^{2} - 2(3x)(4y) + 16 {y}^{2} ) \\ - 28(4 {x}^{2} - 2(2x)(y) + {y}^{2}) \\ = 7(9 {x}^{2} - 24xy + 16 {y}^{2}) \\ - 28(4 {x}^{2} - 4xy + {y}^{2})$

$= (63 {x}^{2} - 168xy + 16 {y}^{2} ) \\ - 112 {x}^{2} - 112xy - 28 {y}^{2} \\ = 63 {x}^{2} - 112 {x}^{2} - 168xy \\ - 112xy + 16 {y}^{2} - 28 {y}^{2}$

$- 49 {x}^{2} - 280xy - 12 {y}^{2}$