Find the value of m and n that prove the two triangles are congruent by the HL theorem.

If both triangles are congruent by the HL theorem, then their hypotenuses are equal and at least one of the corresponding legs is equal too.
Hypothenuses:
[tex]13=4m+1[/tex]From this expression, you can calculate the value of m
[tex]\begin{gathered} 13=4m+1 \\ 13-1=4m \\ 12=4m \\ \frac{12}{4}=\frac{4m}{4} \\ 3=m \end{gathered}[/tex]Legs:
[tex]2m+n=8m-2n[/tex]Replace the expression with the calculated value of m
[tex]\begin{gathered} 2\cdot3+n=8\cdot3-2n \\ 6+n=24-2n \end{gathered}[/tex]Now pass the n-related term to the left side of the equation and the numbers to the right side:
[tex]\begin{gathered} 6-6+n=24-6-2n \\ n=18-2n \\ n+2n=18-2n+2n \\ 3n=18 \end{gathered}[/tex]And divide both sides of the expression by 3
[tex]\begin{gathered} \frac{3n}{3}=\frac{18}{3} \\ n=6 \end{gathered}[/tex]So, for m=3 and n=6 the triangles are congruent by HL