Question

72. Calcule o valor numérico de:

a) -X -X^2 -X^3 -X^4 para = -2

b) (a+b) . (a-b) para a= -4 e b = -1/2

Answer 1

a)-2.(-2^2).(-2^3).(-2^4)
-2.-4.+8.-16
+8.+8.-16
64.-16
1024

b)(-4+(-0,5)).(-4-(-0,5)
(-4-0,5).(-4+0,5)
16-2+2-0,25
15,75

Answer 2

a)
$- ( - 2) - {( - 2)}^{2} - {( - 2)}^{3} - {( - 2)}^{4} \\ 2 - 4 + 8 - 16 \\ 10 - 20 \\ - 10$
b)
$(a + b) \times (a - b) = {a}^{2} - {b}^{2} \\ {( - 4)}^{2} - { ( - \frac{1}{2} )}^{2} = \\ 16 - \frac{1}{4} = \\ \frac{64 - 1}{4} = \\ \frac{63}{4} = 15.75$