Solve the Cauchy-Euler equation t2y11ty+27y=0\displaystyle {t}^{{2}}{y}{''}-{11}{t}{y}'+{27}{y}={0} with initial conditions y(1)=1,y(1)=12\displaystyle {y}{\left({1}\right)}=-{1},{y}'{\left({1}\right)}={12}.

y(t)=\displaystyle {y}{\left({t}\right)}=