as they are congruent their equivalent sides are equal, this is:
[tex]\begin{gathered} y+1=x\text{ (1)} \\ 3y=x+3\text{ (2)} \end{gathered}[/tex]
we replace x in equation 2
[tex]\begin{gathered} 3y=y+1+3 \\ 3y-y=y+1+3-y \\ 2y=4 \\ \frac{2y}{2}=\frac{4}{2} \\ y=2 \end{gathered}[/tex]
for x we replace y in equation 1
[tex]\begin{gathered} x=2+1 \\ x=3 \end{gathered}[/tex]
x = 3
y = 2
