Question

Calcule o valor numérico para x4 - 8x3 - x, para:
a) x= 3
b) x= -

20 pontos!!

Answer 1

x⁴ - 8 • 3 - x

A) x = 3

3⁴ - 8 • 3 - 3 =
81 - 24 - 3 =
54

B) x = -2

(-2)⁴ - 8 • 3 - (-2) =
16 - 24 + 2 =
-6

Answer 2

x4 - 8x3 - x, para:

a) x= 3  ==> 3^4 - 8(3)^3 - 3 ==> 81 - 8.27 - 3 ==> 78 - 216 ==> 138

b) x= - 2  ==> (-2)^4 - 8(-2)^3 - (-2) ==> 16 - 8.(-8) + 2 ==> 18 - 64 ==> - 46