Please help me to solve this model..

To say that Q_d = Q_s is equivalent to saying Q_d - Q_s = 0

So you just need to find the p that satisfies 3/ -/ p^2/ -/ 6p/ +/ 4/ =/ 0

Tip: This quadratic will give you two solutions for p, but you'll quickly see that only one makes sense in the problem, since we don't normally deal with negative prices and negative quantities in our universe :-)

After finding the equilibrium price, plug it back in to either of the demand equations to find equilibrium d.

Sorry, here's the cleaned up version...

3\ -\ p^2\ -\ 6p\ +\ 4\ =\ 0

I haven't had my coffee yet.