A.  $\stackrel{\to }{u}=(-2;-1;3).$

B.  $\stackrel{\to }{u}=(1;-2;1)$

C.  $\stackrel{\to }{u}=(0;-2;3)$

D.  $\stackrel{\to }{u}=(-1;-3;4)$

A.  $\stackrel{\to }{{\mathrm{u}}_2}$=(3;2;0).

B.  $\stackrel{\to }{{\mathrm{u}}_3}$=(2;0;-1). 

C.  $\stackrel{\to }{{\mathrm{u}}_1}$=(1;-2;-2).

D. $\stackrel{\to }{{\mathrm{u}}_4}$=(-1;2;-2).

A. T = 1

B. T = 5

C. T = 2

D. T = 10

A.  $\left\{\begin{array}{l}x=-5-2t\\ y=-10-4t\\ z=-15-6t\end{array}\right.$

B. $\left\{\begin{array}{l}x=2+t\\ y=4+2t\\ z=6+3t\end{array}\right.$

C. $\left\{\begin{array}{l}x=1+2t\\ y=2+4t\\ z=3+6t\end{array}\right.$

D. $\left\{\begin{array}{l}x=3+2t\\ y=6+4t\\ z=12+6t\end{array}\right.$

A.  $\left\{\begin{array}{l}x=\frac{12}{5}+7t\\ y=\frac{6}{5}-t\\ z=2+5t\end{array}\right.$

B. $\left\{\begin{array}{l}x=\frac{12}{5}+7t\\ y=\frac{6}{5}+t\\ z=2+5t\end{array}\right.$

C. $\left\{\begin{array}{l}x=\frac{12}{5}-7t\\ y=\frac{6}{5}-t\\ z=-2+5t\end{array}\right.$

D. $\left\{\begin{array}{l}x=-\frac{12}{5}+7t\\ y=\frac{6}{5}+t\\ z=2+t\end{array}\right.$

A.  $\stackrel{\to }{u}=\left(4;-1;3\right)$

B.  $\stackrel{\to }{u}=\left(4;0;-1\right)$

C.  $\stackrel{\to }{u}=\left(4;1;3\right)$

D.  $\stackrel{\to }{u}=\left(4;1;-1\right)$

A.  $\stackrel{\rightharpoonup }{{\text{u}}_{\text{d}}}=(1;-2;0)$

B.  $\stackrel{\rightharpoonup }{{\text{u}}_{\text{d}}}=(2;3;-1)$

C.  $\stackrel{\rightharpoonup }{{\text{u}}_{\text{d}}}=(-3;1;-2)$

D.  $\stackrel{\rightharpoonup }{{\text{u}}_{\text{d}}}=(3;1;2)$

A. (1; -2; 0)

B. (2; 3; -1)

C. (-3; 1; -2)

D. (3; 1; 2)