Question

Решите, пожалуйста примеры
1) (9x+y)(4x-3y)
2) (a+5)(2a-7)
3) (x-4)(x(в квадрате)+2-3)

Answer 1

$1)(9x + y)(4x - 3y) = 36 {x}^{2} - 27xy + 4xy - 3 {y}^{2} = 36 {x}^{2} - 23xy - 3 {y}^{2}$
$2) (a + 5)(2a - 7) = 2 {a}^{2} - 7a + 10a - 35 = 2 {a}^{2} + 3a - 35$
$3) (x - 4)( {x}^{2} + 2 - 3) = (x - 4)( {x}^{2} - 1) = {x}^{3} - x - 4 {x}^{2} + 4 = {x}^{3} - 4 {x}^{2} - x + 4$