Which of the following statements are true? Justify your answers.
i) The collection of all Class 5 students is a set.
ii) {«} is the empty set.
iii) No purely imaginary number is a real number.
iv) For any z∈C, if |z| , then ∈R z∈ R .
v) A biquadratic equation must have at least one real root.
vi) The system of equations 2x + 3y + z5 = 1and 5 3x + 2y + z = 5has a unique solution.
vii) The AM of 1,0 − ,1 is greater than or equal to their GM.
viii) ‘A is sufficient for B’ is equivalent to ‘the negative of A is necessary for the
negative of B’.
ix) The Gaussian elimination method can only be applied for solving a system of 4
linear equations if the number of variables is 4.