Question

$15x^3 - {3}^2{} + 4$
При x=-1
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Answer 1

$15x^3 - 3^2 + 4 = 15x^3 - 9 + 4 = 15x^3 - 5 = \boxed{5(3x^3 - 1)}$

При x = -1:

$5(3\cdot (-1)^3 - 1) = 5\cdot (-3 - 1) = 5\cdot (-4) = \boxed{\textbf{-20}}$ .

Ответ: -20.