Prove that if A⊆C , B⊆C, A∪B=C and A∩B=∅ then A=C−B

Find the value of p for which the polynomial 3x^3 -x^2 + px +1 is exactly divisible by x-1, hence factorise the polynomial

What’s the answer ? use the picture to see the problem

Find the nonpermissible replacement for binthis expression.b2/5b +5