\overrightarrow{a}(2,1,-5)\\ 3\overrightarrow{a}(6,3,-15)\\ 3\overrightarrow{a}-\overrightarrow{b}=(6-3;3-2;-15+2)=(3;1;-13);\\ |3\overrightarrow{a}-\overrightarrow{b}|=\sqrt{3^2+1+169}=\sqrt{179} " alt="
\overrightarrow{a}(2,1,-5)\\ 3\overrightarrow{a}(6,3,-15)\\ 3\overrightarrow{a}-\overrightarrow{b}=(6-3;3-2;-15+2)=(3;1;-13);\\ |3\overrightarrow{a}-\overrightarrow{b}|=\sqrt{3^2+1+169}=\sqrt{179} " align="absmiddle" class="latex-formula">