Question 866562
x = side length of the square
w = width of rectangle
L = length of rectangle
-
x=w+5....



But none of the analysis is necessary because your description clearly says that the perimeter of the rectangle and of the square are the same.  The given question is not necessary.  Both perimeters are given as 60 cm.



If there were a different question....
{{{4x=60}}}----for the square, perimeter.
{{{x=60/4}}}
{{{highlight(x=15)}}}, may be useful later.
-
{{{2w+2L=60}}}----begin looking at perimeter of the rectangle.
If {{{x=w+5}}} as given, then {{{w=x-5}}};
From found x, {{{w=15-5}}}, {{{highlight(w=10)}}}.


Now we know two previously unknown values:
{{{x=15}}} and {{{w=10}}};
What about L?  Return again to the perimeter for the rectangle.
{{{2w+2L=60}}}
{{{w+L=30}}}
{{{L=30-w}}}
{{{L=30-10}}}
{{{highlight(L=20)}}}
-
SUMMARY:
{{{highlight(x=15)}}}---side of the square
{{{highlight(w=10)}}}---width of rectangle
{{{highlight(L=20)}}}---Length of rectangle


The <b>question</b> needed to be properly changed.  Maybe such as, "find the length and width of the rectangle, and the side length of the square."