Question 1003934
w width, L length
Area now, wL.
Area changed, (w+1)(L+3).


{{{(w+1)(L+3)-wL=19}}}
{{{wL+L+3w-wL=19}}}
{{{L+3w=19}}}
This is all you can do.  You can solve for w in terms of L, or solve for L in terms of w.