Question

ДАЮ 30 БАЛЛОВ ПОМОГИТЕ СРОЧНО c ДЕЙСТВИЯМИ
(2b-c)(2b+c)-2c^2 =
(1-3k)(1+3k)-k^2=

Answer 1

$1)(2b - c)(2b + c) - 2 {c}^{2} = 4 {b}^{2} - {c}^{2} - 2 {c}^{2} = 4 {b}^{2} - 3 {c}^{2} \\ 2)(1 - 3k)(1 + 3k) - {k}^{2} = 1 - 9{k}^{2} - {k}^{2} = 1 - 10 {k}^{2}$