14. Let \( a \) and \( b \) belong to a ring \( R \) and let \( m \) be an integer. Prove that \( m \cdot(a b)=(m \cdot a) b=a(m \cdot b) \)

b) Hallar el valor de \( x \) en la siguiente proporción \( \quad \frac{x+3}{5}=\frac{x-3}{2} \)

Match each polynomial with its description. monomial \( 3 x y \) binomial \( 3 x-7 y+2 z \) c. \( x+y \)

a) Hallar el valor de " \( x \) " en cada razón \( \quad \frac{x+7}{2}=5 \)

\( \begin{array}{l}\text { xample:- Solve the following system of equations by L } \\ \text { Decomposition } \\ \text { decomposition } \\ x_{1}+5 x_{2}+12 x_{3}=47 \\ x_{1}+2 x_{2}+3 x_{3}=14 \\ 2 x_{1}+4 x_{2}+3 x_{3}=19\end{array} \)

Solve: \( y^{2}-27=0 \)