Question 945365
The length, width, and diagonal form a right triangle.
{{{L^2+W^2=D^2}}}
{{{(W+7)^2+W^2=17^2}}}
{{{W^2+14W+49+W^2=289}}}
{{{2W^2+14W-240=0}}}
{{{W^2+7W-120=0}}}
{{{(W+15)(W-8)=0}}}
Only positive solutions make sense here.
{{{W-8=0}}}
{{{W=8}}}
So then,
{{{L=8+7}}}
{{{L=15}}}