(x-2y)(-3x + y) − 3(5x² — y²)

(x-2y)(-3x + y) − 3(5x² — y²)

$(x - 2y)( - 3x + y) - 3(5 {x}^{2} - {y}^{2} ) =$

$x( - 3x + y) - 2y( - 3x + y) - 3(5 {x}^{2} - {y}^{2} ) =$

$- 3 {x}^{2} + xy - 2y( - 3x + y) - 3(5 {x}^{2} - {y}^{2} ) =$

$- 3 {x}^{2} + xy + 6xy - 2 {y}^{2} - 3(5 {x}^{2} - {y}^{2} ) =$

$- 3 {x}^{2} + 7xy - 2 {y}^{2} - 3(5 {x}^{2} - {y}^{2} ) =$

$- 3 {x}^{2} + 7xy - 2 {y}^{2} - 15 {x}^{2} + 3 {y}^{2} =$

$- 18 {x}^{2} + 7xy - 2 {y}^{2} + 3 {y}^{2} =$

$- 18 {x}^{2} + 7xy + {y}^{2}$