State which of the following numbers are irrational: (i) 3 − √7/25 (ii) −2/3 + ∛2 (iii) 3/√3 (iv) − 2/7 ∛5 (v) (2 − √3) (2 + √3) (vi) (3 + √5)^2 (vii) (2/5 √7)^2 (viii) (3 − √6)^2.