## Elementary Linear Algebra 7th Edition

a) $W$ is the straight line in the $xy$-plane given by the equation $x=2y$ and passing through the origin. b) $(2 t, t)=t(2,1)$, hence $(2,1)$ is a basis for $W$. c) The dimension of $W$ is $1$.
Assume the subspace $W=\{(2 t, t) : t \text { is a real number }\}$, then a) $W$ is the straight line in the $xy$-plane given by the equation $x=2y$ and passing through the origin. b) $(2 t, t)=t(2,1)$, hence $(2,1)$ is a basis for $W$. c) The dimension of $W$ is $1$.