Question

Write the following in roster form.

The set of all positive roots of the equation (x − 1)(x + 1)(x² − 1) = 0

Answer 1

The set of positive roots of the equations

(x – 1)(x + 1)(x² – 1) = 0

(x – 1)(x + 1)(x + 1)(x – 1) = 0

(x + 1)² (x – 1)² = 0

(x + 1)² = 0 or (x – 1)² = 0

x + 1 = 0 or x – 1 = 0

x = –1 or x = 1

A = {1}