Question

Calcule o valor numérico da "função do 2 grau" f(X): - 2x* -7X -6 , quando :
a) f(-2):
b) f(2):

Answer 1

Para $f(-2)$:
$-2*(-2)^2 - 7*(-2) - 6 = \\ -2 * 4 + 14 - 6 = \\ -8 + 14 - 6 = \\ -14 + 14 = 0$

Para $f(2)$:
$-2*(2)^2 - 7*(2) - 6 = \\ -2*4 - 14 - 6 = \\ -8 - 14 - 6 = -28$

Portanto:
$f(-2) = 0$
$f(2) = -28$

Answer 2

a)

f(x) = - 2x² - 7x - 6
f(-2) = - 2.(-2)² - 7.(-2) - 6
f(-2) = - 2.4 + 14 - 6
f(-2) = - 8 + 8
f(-2) = 0

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b)
f(x) = - 2x² - 7x - 6
f(2) = - 2.2² - 7.2 - 6
f(2) = - 2.4 - 14 - 6
f(2) = - 8 - 20
f(2) = - 28