4p2+4C2−4p3
npr=n![n−r]!andnCr=n![n−r]!r!
= 4![4−2]!+4![4−2]!2!−4![4−3]!=4!2!+4!2!2!−4!1!
= 4*3*2!2!+4*3*2!2!2!−4*3*2*11!
12 + 6 - 24 = -6