Find the general solution to the homogeneous differential equationd$2$ydx$213$dydx$+42$y$=0$

The solution has the formy$=$C$1$f$1($x$)+$C$2$f$2($x$)$with f$1($x$)=$

e$7$x

and f$2($x$)=$

e$6$x

Left to your own devices, you will probably write down the correct answers, but in case you want to quibble, enter your answers so that f$1,$f$2$ are normalized with their value at x$=0$ equal to $1.$