Solve for m - hp = d for p please actually help this is my first assignment of the year and can’t fail

Well, you just have to manipulate the equation a little bit. We can start by isolation the “p” gem:
m - hp = d
-hp = d - m.
Then, all we have to do is isolate the “p” variable:
p = -(d - m) / h
p = ( -d + m ) / h