Given vectors \(\vec{a} = (-1,2,1)\),
\(\vec{b} = (0,-1,1)\), and
\(\vec{c} = (-2,0,1)\), find the length
of the vector \(\vec{u} =\vec{ a} - 2\vec{b} + \vec{c}\).
We are given points \( A = [2,1] \), \( B = [7,2] \), and \( T = [4,3] \), where point \( T \) is the centroid of triangle \( ABC \). Find the coordinates of \( C \), which is the vertex of \( ABC \).
Given the vectors \( \vec{a} \), \( \vec{b} \), and \( \vec{c} \) shown in the picture, express the vector \( \vec{c} \) as a linear combination of vectors \( \vec{a} \) and \( \vec{b} \).