Срочно дам 100 баллов

3.
О(0; 0; 0)
А(3; 1; -2)

$\frac{x-x_0}{x_1-x_0} = \frac{y-y_0}{y_1-y_0} = \frac{z-z_0}{z_1-z_0}$

$\frac{x-0}{3-0} = \frac{y-0}{1-0} = \frac{z-0}{-2-0} =t\\ \left \{ \begin{array}{c}x=3t\\y=t\\z=-2t\end{array}\right } \right.$

4.
$\frac{x-x_0}{m_x} = \frac{y-y_0}{m_y} = \frac{z-z_0}{m_z} \\\\ \frac{x-5}{3} = \frac{y+4}{2} = \frac{z+5}{4}$

5.
$R^2=(x-x_0)^2+(y-y_0)^2+(z-z_0)^2\\\\ 4=(x+3)^2+y^2+(x-4)^2$