Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients. (i) x^2 - 2x - 8 (ii) 4s^2 - 4s + 1 (iii) 6x^2 - 3 - 7x (iv) 4t^2 + 8u (v) t^2 - 15 (vi) 3x^2 - x - 4