Question

determine o valor numerico de:

$a) 3.(x - 8), para,x = 12$
$b)3x + x^{3}, para,x = 4$
$c) x^{3} - x^{2} - 2x, para,x = -2$
$d) \frac{5x}{2}, para,x = -3$
$e) 1,5x^{2} + x - 3,2, para,x = 5$

Answer 1

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a) x = 12

= 3.(x - 8)
= 3.(12 - 8)
= 3.4
= 12
**********************
b) x = 4

= 3x + x³
= 3.4 + 4³
= 12 + 64
= 76
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c) x = - 2

= x³ - x² - 2x
= (-2)³ - (-2)² - 2.(-2)
= - 8 - (4) + 4
= - 8 - 4 + 4
= - 8

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d) x = - 3

 5x     =  5.(-3)       - 15
------      ---------  = -------
  2              2             2

***********************

e) x = 5

= 1,5 x² + x - 3,2

= 1,5.5² + 5 - 3,2

= 1,5.25 + 1,8

= 37,5 + 1,8

= 39,3