Answer :
[tex]6x+3=2x-13\ \ \ \ |subtract\ 2x\\\\
4x+3=-13\ \ \ \ |subtract\ 3\\\\
4x=-16\ \ \ \ |divide\ by\ 4\\\\
x=-4\\\\Solution\ is\ x=-4\\\\\\15=6x-3\ \ \ |add\ 3\\\\
18=6x\ \ \ |divide\ by\ 6\\\\
x=3\\\\Solution\ is\ x=3.[/tex]Answer here