1. Fie expresia \( E(x)=\left(\frac{3 x+6}{x^{2}+x-2}-\frac{2}{x+1}+\frac{4 x}{x^{2}-1}\right): \frac{1}{x-1} \), unde \( x \in \mathbb{R} \backslash\{-2 ;-1 ; 1\} \) 10p a) Arătaţi că \( x^{2}+x-2=(x-1)(x-2), \forall x \in \mathbb{R} \). 10p b) Arătaţi că \( E(x)=5, \forall x \in \mathbb{R} \backslash\{-2 ;-1 ; 1\} \)

(ס) \( \frac{4(a-9)}{36(9-a) x^{3}} \)

Simplify the following expressions fully: \( 1.2 .1 \quad(x+2)\left(x^{2}-x+3\right) \)

Jika \( \left(\begin{array}{cc}-2 & 2 \\ 5 & y\end{array}\right)\left(\begin{array}{ll}5 & 3 \\ x & 4\end{array}\right)=\left(\begin{array}{cc}-6 & 2 \\ 27 & 19\end{array}\right) \), cari nilai \( x \) dan \( y \). If \( \left(\begin{array}{cc}-2 & 2 \\ 5 & y\end{array}\right)\left(\begin{array}{ll}5 & 3 \\ x & 4\end{array}\right)=\left(\begin{array}{cc}-6 & 2 \\ 27 & 19\end{array}\right) \), find the value of \( x \) and \( y \).

FACTORIZAR APLICANDO CASOS COMBINADOS DE FACTDRES A) \( \cdot x^{3}+5 x^{2}-4 x-20 \) B) \( \cdot 75 x^{5}+60 x^{4}+12 x^{3} \) C) \( \cdot 2 x^{2}-18 \) d) \( x^{3}+x^{2}-9 x-9 \) e) \( x^{4}-81 \)

1.Решить уравнение: \( \begin{array}{lll}\text { a) } \sqrt{x+3}=\sqrt{5-x} & \text { б) } \quad \sqrt{12+3 x}=2 & \text { в) } \quad x=1+\sqrt{x+11}\end{array} \)