Question

Seja a função F(x)= 4.2*, Determine:

a) x,para F(×)=256

b) F(-2)

Answer 1

A)

$f(x) = 4. 2^{x}$
$256 = 4. 2^{x}$
$\frac{256}{4} = 2^{x}$
$64 = 2^{x}$
$2^{6} = 2^{x}$
$x = 6$

b)

$f(x) = 4. 2^{x}$
$f(-2) = 4. 2^{-2}$
$f(-2) = 4. (\frac{1}{2}) ^{2}$
$f(-2) = 4. \frac{1}{4}$
$f(-2) = \frac{4}{4}$
$f(-2) = 1$