Using 2x2 Matrices for Plane Transformations Practice Test

First rotate points $90^\circ$ counterclockwise using $$R=\begin{pmatrix}0&-1\1&0\end{pmatrix},$$ then reflect across the $x$-axis using $$F=\begin{pmatrix}1&0\0&-1\end{pmatrix}.$$ What is the combined transformation matrix (apply $R$ first, then $F$)?

A linear transformation maps the unit square to a parallelogram. If the transformation matrix is $$A=\begin{pmatrix}1&2\0&1\end{pmatrix},$$ what is the area magnification factor $|\det(A)|$?