Factorise the following expressions fully: \( \begin{array}{ll}1.1 .1 & 4 x-x^{3} \\ \text { 1.1.2 } & x^{2}+15 x-54 \\ 1.1 .3 & y-x y+x-1\end{array} \)

(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. 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.

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

Exercice N1 \( \begin{array}{lll}\text { Simplifier les expressions suivantes puis calculer leur valeur: } \\ \begin{array}{lll}\text { 1. } a=5^{1,7} \times 5^{1,3} & \text { 2. } b=\left(2^{-\frac{1}{5}}\right)^{6} & \text { 3. } c=4^{-0,7} \times \times \frac{1}{4^{0,3}}\end{array} & \text { 4. } d=\frac{6^{4,5} \times 6^{2,3}}{\left(6^{1,6}\right)^{3}}\end{array} \)