What is (12x3 - 6x + 4) - ( - 3x2 + 4x + 3)?
The difference of these two polynomials is the same as the sum of polynomials
(12x3 - 6x + 4) + (3x2 - 4x - 3)
We distributed the minus sign by flipping every sign in the second polynomial. We flipped them all upside - down too, even though you probably can't tell. We may have gotten a little flip - happy.
We do the new polynomial addition problem and find
12x3 + 3x2 - 10x + 1.