Solve.

y100y=e7t\displaystyle {y}{''}-{100}{y}={e}^{{{7}{t}}}

The general solution will be

y(t)=c1e10t+c2e10t+\displaystyle {y}{\left({t}\right)}={c}_{{{1}}}{e}^{{{10}{t}}}+{c}_{{{2}}}{e}^{{-{10}{t}}}+