quadratic equation

Question

The condition that the roots of equation x3+3px2+3qx+r=0 satisfied, is

Answer 1

Looking at the coefficients reminds me of the "1 3 3 1" row of Pascal's triangle, which reminds me that (A+B)³ = A³ + 3A²B + 3AB² + B³, so with A = x and B = p, it should all work out.