Firstly, you have to $\bold{simplify}$ each of the sides of your equation
$\bold{6-2p-p+9\downarrow}$
$\bold{6+(-2p)=p+9\downarrow}$
$\rightarrow\bold{-2p+6=p+9}$
Now that you have that portion out of the way, we could move on to our second step... which is to $\bold{subtract}$ by the value of $\bold{p}$ on each of your sides
$\bold{-2p+6-p-p+9-p\downarrow}$
$\rightarrow\bold{-3p+6-9}$ (you get this because we solve the particular equation we added above)
Thirdly, you have to $\bold{subtract}$ by the number $\bold{6}$ on each of your sides
$\bold{-3p+6-6=9-6\downarrow}$
$\bold{Cancel:6-6}$ because it equals to $\bold{0}$
$\bold{Keep:9-6}$ because it brings us closer and closer to the answer of $\bold{p}$
Fourthly, we have to $\bold{divide}$ by the number $\bold{-3}$ on each of your sides
$\bold{\frac{-3p}{-3}=\frac{3}{-3}}$
$\boxed{\boxed{\bold{Answer:p=-1}}}$ $\checkmark$