A.  $\stackrel{\to }{c} = 3\stackrel{\to }{a} + 2\stackrel{\to }{b}$

B.  $\stackrel{\to }{c} = 3\stackrel{\to }{a} - 2\stackrel{\to }{b}$

C.  $\stackrel{\to }{c} = 2\stackrel{\to }{a} + 3\stackrel{\to }{b}$

D.  $\stackrel{\to }{c} = 2\stackrel{\to }{a} - 3\stackrel{\to }{b}$

A.  $\stackrel{\to }{b}=-\frac{1}{8}\stackrel{\to }{a}-\frac{1}{4}\stackrel{\to }{c}$

B.  $\stackrel{\to }{b}=\frac{1}{8}\stackrel{\to }{a}-\frac{1}{4}\stackrel{\to }{c}$

C.  $\stackrel{\to }{b}=-\frac{1}{2}\stackrel{\to }{a}-4\stackrel{\to }{c}$

D.  $\stackrel{\to }{b}=-\frac{1}{8}\stackrel{\to }{a}+\frac{1}{4}\stackrel{\to }{c}$

A. $\stackrel{\rightharpoonup }{\mathrm{b}}=\left(4;2;-4\right)$

B.  $\stackrel{\rightharpoonup }{\mathrm{b}}=\left(-4;-2;4\right)$

C. $\stackrel{\rightharpoonup }{\mathrm{b}}=\left(4;2;-4\right) \mathrm{hoặc} \stackrel{\rightharpoonup }{\mathrm{b}}=\left(-4;-2;4\right)$

D. $\stackrel{\rightharpoonup }{\mathrm{b}}=\left(12;6;-12\right) \mathrm{hoặc} \stackrel{\rightharpoonup }{\mathrm{b}}=\left(-12;-6;12\right)$