4p2 - 6p = 0
p=0 or p=1.5
Guest got the right answers but here's an explanation:
Factor out a p from both terms.
(p)(4p - 6) = 0
Set each factor equal to zero.
(If either one was zero, then the whole thing equals zero.)
Either p = 0 or 4p - 6 = 0
p = 6/4 = 1.5