4. La relación \( y= \pm \sqrt{x} \) ¿es una función? Explica. 5. Si \( f(x)=x^{2} \) y \( g(x)=\sqrt{x} \), ¿son funciones \( f \) y \( g \) ? Explica por qué.

Use the properties of logarithms to evaluate each of the following expressions. \( \begin{array}{l}\text { (a) } 2 \log _{12} 2+\log _{12} 3=\square \\ \text { (b) } \quad \ln e^{2}-\ln e^{11}=\square\end{array} \)

Fill in the missing values to make the equations true. (a) \( \log _{4} 3-\log _{4} 7=\log _{4} \square \) (b) \( \log _{5} 7+\log _{5} \square=\log _{5} 42 \) (c) \( 2 \log _{9} 5=\log _{9} \square \)

Use the properties of logarithms to evaluate each of the following expressions. \( \begin{array}{l}\text { (a) } \log _{6} 9+2 \log _{6} 2=\square \\ \text { (b) } \ln e^{8}-\ln e^{2}=\square\end{array} \)

Use the properties of logarithms to evaluate each of the following expressions. \( \begin{array}{l}\text { (a) } \ln e^{5}-8 \ln e^{2}=\square \\ \text { (b) } \log _{6} 18+\log _{6} 2=\square\end{array} \)

7. Winnie wrote the following riddle: I am a number between 60 and 100 . My ones digit is two less than my tens digit. I am a prime number.