Apply the Laplace transform to the differential equation, and solve for Y(s)\displaystyle {Y}{\left({s}\right)}. DO NOT solve the differential equation. Recall: h(tα)\displaystyle {h}{\left({t}-\alpha\right)} is the unit step function shifted to the right α\displaystyle \alpha units.

y+9y=2(t3)h(t3)2(t6)h(t6),y(0)=y(0)=0\displaystyle {y}{''}+{9}{y}={2}{\left({t}-{3}\right)}{h}{\left({t}-{3}\right)}-{2}{\left({t}-{6}\right)}{h}{\left({t}-{6}\right)},\quad{y}{\left({0}\right)}={y}'{\left({0}\right)}={0}

Y(s)\displaystyle {Y}{\left({s}\right)} =