Let
x---------> the length of each side of the original garden
we know that
The area of the square is equal to
\(A= b^{2}\)
where
b is the length side of the square
in this problem
\(b=(x+7)\ m\\ A=(x+7)^{2}\\A=169\ m^{2}\)
so
\((x+7)^{2}=169\\x+7=13\\ x=13-7\\x= 6\ m\)
therefore
the answer is
the length of each side of the original garden is \(6\ m\)
