Answer
$y=-2e^{6-6x}+5$
Work Step by Step
$y''+6y'=0$ which has the characteristic equation $t^2+6t=0$ with solutions $t=0$ and $t=-6$
General solution: $c_1e^{-6x}+c_2$
Plug in the values: $y(1)=3$ and $y'(1)=12$ giving $c_1=-2e^{6}$, $c_2=6$
Hence, $y=-2e^{6-6x}+5$
