Answer
a) $W$ is the straight line in the $xy$-plane given by the equation $x=0$ (the $y$-axis) and passing through the origin.
b) $(0, t)=t(0,1)$, hence $(0,1)$ is a basis for $W$.
c) The dimension of $W$ is $1$.
Work Step by Step
Assume the subspace $W=\{(0, t) : t \text { is a real number }\}$, then
a) $W$ is the straight line in the $xy$-plane given by the equation $x=0$ (the $y$-axis) and passing through the origin.
b) $(0, t)=t(0,1)$, hence $(0,1)$ is a basis for $W$.
c) The dimension of $W$ is $1$.
