Question

ПОМОГИТЕ ПОЖАЛУСТО БИРО НАДО !!!

Answer 1

$(2ab - 5c) + (3 {a}^{2} b + 3c) = 2ab - 5c + 3 {a}^{2} b + 3c = \\ = 2ab - 2c + 3 {a}^{2} b$

$(2ab - 5c) - (3 {a}^{2} b + 3c) = 2ab - 5c - 3 {a}^{2} b - 3c = \\ = 2ab - 8c - 3 {a}^{2} b$

$6x( {x}^{2} - 2) = 6 {x}^{3} - 12x$

$(2a - b)(3a - 4b) = 6 {a}^{2} - 8ab - 3ab + 4 {b}^{2} = \\ = 6 {a}^{2} - 11ab + 4 {b}^{2}$