Question 847300
L length, w width.
L=w+10.
{{{L*w=144}}}
{{{(w+10)w=144}}}
{{{w^2+10w=144}}}
{{{w^2+10w-144=0}}}
Do you want to look for a factorization?


If not, then, discriminant is {{{100-4(-144)=100+4*144=676}}}.
{{{676=4*169=4*13^2=2^2*13^2=26^2}}}.

You want the general solution choice which uses the positive square root.
{{{w=(-10+sqrt(26^2))/2}}}
{{{w=(26-10)/2}}}
{{{highlight(w=8)}}} which means {{{highlight(L=18)}}}