WeBWorK Standalone Renderer

Let $A = \left[\begin{array}{cc} -2 &4\cr 1 &-4\cr 1 &0 \end{array}\right].$ Find an orthonormal basis of the image of $A$ .

$\Bigg\lbrace$ $\left[\Rule{0pt}{3.6em}{0pt}\right.$ $\left]\Rule{0pt}{3.6em}{0pt}\right.$ , $\left[\Rule{0pt}{3.6em}{0pt}\right.$ $\left]\Rule{0pt}{3.6em}{0pt}\right.$ $\Bigg\rbrace.$