3. In the complex number system, which of the following is equal to \( 3 i(1+i)- \) \( (1-i)^{2} \) ? (Note: \( i=\sqrt{-1}) \) A. \( -3+i \) B. \( -3+5 i \) C. \( 3+i \) D. \( 3+5 i \)

5) \( (x+2)^{4}-4(x+2)^{2}-5=0 \)

If the system \( \left\{\begin{aligned}-4 x-5 y-4 z=-3 \\ -5 x+7 y-8 z=-7 \\ -6 x+19 y+h z=k\end{aligned}\right. \) has infinitely many solutions, then \( k=\square \) and \( h= \)

42. \( \frac{3 x+y}{2 x+3+z} \quad \operatorname{per} x=-\frac{1}{9} \quad y=\frac{1}{2} \quad, \quad z=\frac{2}{9} \)

\( \log _{3}(2 x-5)=-2 \) Simplify your ansh

For the following system to be consistent, \( \left\{\begin{array}{l}6 x_{1}-3 x_{2}-2 x_{3}=-6 \\ 5 x_{1}-8 x_{2}+k x_{3}=-4 \\ -7 x_{1}+4 x_{2}+7 x_{3}=8\end{array}\right. \) we must have \( k \neq \square \) You may enter your answer as a fraction.