5 marks Let P3 be the vector space of all real polynomials of degree at most 3 Let S p P3 p x ax b a b R S p P3 p x bx bx b R and S3 p P3 p x x b b R Determine whether S S or S3 are vector subspaces of P3 giving full reasons for your answers For those who are vector subspaces determine their dimension