If x264+y225=1\displaystyle {\frac{{{x}^{{2}}}}{{{64}}}}+{\frac{{{y}^{{2}}}}{{{25}}}}={1} and y(1)=4.96\displaystyle {y}{\left({1}\right)}={4.96}, find y(1)\displaystyle {y}'{\left({1}\right)} by implicit differentiation.

y(1)\displaystyle {y}'{\left({1}\right)} =