(7) Dari barisan aritmaika diketahui suku ke-10 adalah 41 dan suku ke -5 1dakh 21 . Tentukan: (1) Sukuke-50? (b) Juminh 10 suku pertama?

\( 1, \gamma, \times d \),

6 Find theinunse of peint \( (t, s) \) with respat (ti) the orcle \( n^{2} h y^{2}-9 n<6 y=3 \) Ansi \( (6,7) \)

\( f(x)=\frac{x-1}{x-4} \) and \( f^{-1}(x) \) is the inverse of \( f \), what is the value of \( f^{-1}(4) ? \) \( \begin{array}{llll}\text { A) } 5 & \text { (B) } 6 & \text { (C) } 8 & \text { (D) } 10\end{array} \)

Soit \( x \in \mathbb{R}^{+} \)Montrer que : \( \frac{1}{1+\sqrt{x}}=1-\sqrt{x} \)

\( \Delta_{\text {mix }} S=-R\left(x_{1} \operatorname{Ln} x_{1}+x_{2} \operatorname{Ln} x_{2}\right) \)