Verified Answer :

\(s^2=169\iff s=-13\ or\ s=13\\\\because:\\\\(-13)^2=169\ and\ 13^2=169\)

\(169 = s^{2}\)

Square-rooting on both sides, we get,
\(\sqrt{169 } = (+-)\sqrt{ s^{2} }\)

\(\sqrt{13*13 } = (+-)\sqrt{ s^{2} }\)

\(\sqrt{ 13^{2} } =(+-)\sqrt{ s^{2} }\)

Since, the square cancels out square- square root sign, we have

\(13 = (+-)s\)

\((+-)s = 13\)

So, when "s" is positive, the value of "s" is 13
and when "s" is negative, the value of "s" is -13

So, the values of "s" are 13 , -13