Given,
A= (-7, 8, 1).
B= (8, 7, 7)
The value of ||AB|| is,
[tex]\begin{gathered} \mleft\Vert AB\text{ }\mleft\Vert\text{ = }A.B\mright?\mright? \\ \end{gathered}[/tex]The value of A.B is ,
[tex]\begin{gathered} A\mathrm{}B=(-7.8+8.7+1.7) \\ AB=(-56+56+7) \\ AB=7 \end{gathered}[/tex]Hence, the value is 7.