Question

Решите плиз буду благодарен​

Answer 1

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Answer 2

а)

$(c - 9)(c - 3) - 6c(3c - 2) = \\ = {c}^{2} - 9c - 3c + 27 - 18 {c}^{2} + 12c = \\ = - 17 {c}^{2} + 27$

б)

$4a(a - 5) - {(a - 10)}^{2} = \\ = 4 {a}^{2} - 20a - {a}^{2} + 20a - 100 = \\ = 3 {a}^{2} - 100$

в)

${(b + 2)}^{2} - 12b = {b}^{2} + 4b + 4 - 12b = \\ = {b}^{2} - 8b + 4$