a) $u$ and $w$ are parallel
b) $u$ is parallel to $v + w$
c) $v$ and $w$ are orthogonal
d) $u$ is orthogonal to $v + w$
I chose d) since $u\cdot(v+w) = u\cdot v + u\cdot w$.
a) $u$ and $w$ are parallel
b) $u$ is parallel to $v + w$
c) $v$ and $w$ are orthogonal
d) $u$ is orthogonal to $v + w$
I chose d) since $u\cdot(v+w) = u\cdot v + u\cdot w$.