$\displaystyle y^{\prime \prime} + 6 y^{\prime} + 9 y = 0$

Initial Conditions:

$\displaystyle y(0)=3,\quad y^{\prime}(0)=-7$

So, I determined the general solution should look like this:

$\displaystyle Ae^{-3x}+Be^{-3x}=0$

When Y(0)=3

[Math]3=A+B[/tex]

And when Y'(0)=-7

$\displaystyle

-7=-3A-3B

$

Im stuck here. Anytime I try and solve for one variable, I get

-7=-9 which is a totally false statement.

What do I do from here?