Answer :
[tex] \left \{ {{y=6x} \atop {y=5x+7}} \right. \\\\Substitution\ method\\\\
6x=5x+7\ \ \ | subtract\ 5x\\\\
x=7\\
y=6*7=42[/tex]
[tex]\left\{\begin{array}{ccc}y=6x\\y=5x+7\end{array}\right\\\\subtitute\ y=6x\ to\ the\ second\ equation\\\\6x=5x+7\ \ \ \ \ |subtract\ 5x\ fron\ both\ sides\\\boxed{x=7}\\\\subtitute\ value\ of \x=7\ to\ the\ equation\ y=6x:\\\\y=6\cdot7\\\boxed{y=42}\\\\Answer:\\ \left\{\begin{array}{ccc}x=7\\y=42\end{array}\right[/tex]
