Question

F(x) = x+2/x (x número real não nulo)
Determine:
*F(-1):
*F(4):
*O valor de x para f(x)=6

Answer 1

$f(x)=\dfrac{x+2}{x}$

$f(-1)=\dfrac{-1+2}{-1}=\dfrac{1}{-1} \iff \boxed{f(-1)=-1}$

$f(4)=\dfrac{4+2}{4}=\dfrac{6}{4} \iff \boxed{f(4)=\dfrac{3}{2}}$

$f(x)=6 \iff \dfrac{x+2}{x}=6 \iff x+2=6x \iff 5x=2 \iff \boxed{x=\dfrac{2}{5}}$