Rationalize the denominator of \( \frac{7}{2 + \sqrt{3}} \).

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

\( 67.04 cm ^ { 2 } = \frac { \sqrt { 26 a } } { 2 } h \)

vantes: \( A(x)=x^{3}+x^{2}+x-3 \) \( B(x)=(2 x+1)^{3}-(x+1)^{3} \) \( C(x)=8 x^{3}-1+4(2 x-1) \) \( D(x)=9 x^{2}-4-7(3 x-2)(x+1) \) Exercice \( 34: \) Soit \( a \) et \( b \) deux noml non nuls. Calculer \( a^{-2} b\left(a^{2} b^{-1}\right)^{4} a^{-3} b^{2} \)

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

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