Find the best approximation to z by vectors of the form c₁v₁ + c₂v₂

z=
[ 3 ]
[ 3 ]
[ 0 ]
[-1]

,v₁=
[ 3 ]
[ 0 ]
[-1 ]
[-2 ]

,v₂=
[ 3 ]
[-2 ]
[ 3 ]
[ 3 ]