2 Reduce cada grupo de fracciones algebraicas al co- mún denominador. Compara respuestas con tus compañeros. a. \( \frac{x-1}{x+2}, \frac{x+1}{x-2}, \frac{3 x}{x^{2}-2 x-8} \) b. \( \frac{x}{x-1}, \frac{8}{2 x-3}, \frac{3 x}{x+1} \) c. \( \frac{2 x+1}{x}, \frac{8-x}{x+4} \) d. \( \frac{x+8}{x-3}, \frac{11}{4 x^{2}}, \frac{x^{2}+7}{x} \)

-простіть вираз: \( \begin{array}{ll}15 \mathrm{~m}^{2} \cdot\left(4 \mathrm{~m}^{3}\right)^{2} ; & \text { 2) }-0,5 \mathrm{~m}^{5} \cdot\left(2 \mathrm{~m}^{3}\right)^{4} \\ \left.-3 \mathrm{a}^{3} \mathrm{~b}^{4}\right)^{4} \cdot\left(-\frac{1}{8} a^{3} b\right) ; & \text { 4) }\left(-\frac{4}{5} m n^{4}\right)^{3} \cdot 25 m^{4} \mathrm{n}\end{array} \)

Find \( n \), \( 3 n-6=18 n^{2} \) A) 0.654 (B) -0.488 (C) 0.654 OR -0.488 (D) No real roots

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 \( 240 \mid a^{4}-1 \).

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