To subtract polynomials, you first need to reverse the sign of each term we are subtracting, then you add the polynomials as explained in "adding polynomials".

For example: 512v⁵+ 99w⁵ - (600v⁵ - 100w⁴) = 512v⁵+ 99w⁵ - 600v⁵ + 100w⁴= -88v⁵ + 99w⁵ + 100w⁴