Use properties of logarithms to expand each logarithmic expression as much as possible. Evaluate logarithmic expressions without using a calculator if possible. \( \log _{\mathrm{b}}\left(\mathrm{z}^{5} \mathrm{y}\right) \) \( \log _{\mathrm{b}}\left(\mathrm{z}^{5} \mathrm{y}\right)=\square \)

f) \( (-15 a b c+12 a b-9 a c-3 a) \div(-3 a) \)

3. At a school, \( 40 \% \) of the sikthegrade students said that hip-hop is their favorite kind of music. If 100 sixth-gade students preler hip hop music, how many sixth-grade studer are at the school? Explain or show your reasoning.

(Express \( \frac{6}{7 h}-\frac{3-4 g}{14 h} \) as a single fraction in its simplest form. Ungkapkan \( \frac{6}{7 h}-\frac{3-4 g}{14 h} \) sebagai pecahan tunggal dalam bentuk termudah.

3.18. Determine el máximo comun divisor de los enteros \( 15,18,24 \) y escríbalo como una combinación lineal de \( 15,18,24 \). 3.19. Sea \( a \in \mathbb{Z}^{+} \)tal que \( \operatorname{mcd}(240, a)=1 \), probar que \( 240 \mid a^{4}-1 \).

expunencial \( \left.\left(4^{2}\right)\left(2^{3}\right)^{2 x-5}\right)=8 \)