Question

已知集合P的元素为1，m，m∧2-3m-3，若3属于P且-1不属于P，求实数m的值

Answer 1

case 1: m=3
m^2-3m-3 = 9-9-3=-3
P={1,3,-3}
accept case 1

case 2: m^2-3m-3 =3
m^2-3m-3 =3
m^2-3m-6=0
m= (3+√33)/2 or (3-√33)/2
accept case 2

ie
m=3 or (3+√33)/2 or (3-√33)/2