2021-II-23

$P(7,-5)$ is reflected with respect to the $y$-axis to $Q$, then $Q=(-7,-5)$.

$Q(-7,-5)$ is rotated clockwise about the origin through ${90}^{\circ }$ to $R$, then $R=(-5,7)$.

Therefore, the $x$-coordinate of $R$ is $-5$.