Which of the following expressions are polynomials? Justify your answer:
(i) 8
(ii) √3x 2 – 2x
(iii) 1– √5x
(iv) 1/5x^2 + 5x +7
(v) (x−2)(x−4)/ x
(vi) 1/ x+1
(vii) 1/ 7 a^3 – 2 /√3 a^2 + 4a–7
(viii) 1/2x