Suppose a subspace is spanned by the set of vectors shown.
$\lbrace \left[\begin{array}{c}2\\-4\\\end{array}\right], \left[\begin{array}{c}-7\\14\\\end{array}\right] \rbrace$
Find a basis for the subspace, using the method of transforming a matrix to echelon form, where the columns of the matrix represent vectors spanning the subspace.
Basis = $\lbrace$ $\left[\Rule{0pt}{2.4em}{0pt}\right.$$\left]\Rule{0pt}{2.4em}{0pt}\right.$ $\rbrace$.
What is the dimension of the subspace?