\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Find the single matrix representing a horizontal stretch of scale factor 4 followed by a reflection in the \(x\)-axis.
$$ \mathbf{T} = \begin{pmatrix}\input{145145}{}{3em}{2em}{}{} & \input{245145}{}{3em}{2em}{}{}\\ \input{345145}{}{3em}{2em}{}{} & \input{445145}{}{3em}{2em}{}{}\\ \end{pmatrix}$$