Scrivi un polinomio di grado 5 , nelle variabili a e \( b \), ordinato e completo ri- spetto alla variabile a.

\( \left\{ \left. \begin{array} { l } { a - 5 < 2 a + 3 } \\ { 3 a - 2 < a - 6 } \end{array} \right. \Rightarrow a \in ? \right. \)

23. Find the equation of a line. Whose intercepts on \( x \) and \( y \) axis are 4 and -6 .

b) \( 2 x y-1=5 \) f) \( 3 x x-1=8 \)

20 If \( \frac{a}{b}=\frac{c}{d}=\frac{3}{5} \), then \( \frac{a+c}{b+d}=\ldots \ldots \ldots \ldots \) \( \begin{array}{llll}\text { (a) } \frac{5}{3} & \text { (b) } \frac{3}{5} & \text { (c) } \frac{6}{5} & \text { (d) } \frac{5}{6}\end{array} \)

13 If \( \frac{a}{b}=\frac{b}{c}=2 \), then \( \frac{a}{c}=\ldots \ldots \ldots \ldots \) \( \begin{array}{lll}\text { (a) } 2 & \text { (b) } 4 & \text { (c) } 6\end{array} \)