Question

ПОМОГИТЕ ПЖЖППЖРЖПЖПЖРЖ​

Answer 1

$7 {a}^{2} (3a + 1) - 2a(7 {a}^{2} - 3) = 21 {a}^{3} + 7 {a}^{2} - 14 {a}^{3} + 6a = 7 {a}^{3} + 7 {a}^{2} + 6a$