Continuing with Melody's excellent hint, if you need help solving it, here it is:

\(\begin{align*} x^2+8x-884&=0\\ x&=\dfrac{-8\pm\sqrt{64+3536}}{2}\\ x&=\dfrac{-8\pm\sqrt{3600}}{2}\\ x&=\dfrac{-8\pm60}{2}\\ x&=-4\pm30\\ x&=-34, 26 \end{align*}\)

Obviously, the answer cannot be -34 (imagine -34 rows). So the answer is 26.