Find the general solution y=c1y1+c2y2+yp\displaystyle {y}={c}_{{1}}{y}_{{1}}+{c}_{{2}}{y}_{{2}}+{y}_{{p}} to the ODE

yy=x+4y(0)=1,y(0)=7\displaystyle {y}{''}-{y}=-{x}+{4}\quad{y}{\left({0}\right)}={1},\quad{y}'{\left({0}\right)}=-{7}

y\displaystyle {y} =