Forgot to mention but $s,r \in \mathbb{R}$
Could someone help me check whether my solution to the problem is sound? Also is there a better way to solve this? This problem was part of my problem set on the topics of “Gauss-jordan elimination” and “Counting solutions to systems of linear equations(SLE) containing unknown constants” but i didn’t use either of this here and didn’t use a matrix at all actually.