Question

Write the following sets in roster (Tabular) form :
A₂ = {x : x² - 4x -5 = 0}

Answer 1

A₂ = { x : x² − 4x − 5 = 0}

∴ x^{2 −} 4x − 5 = 0

⇒ x² − 5x + x − 5 = 0

⇒ x (x − 5) + 1 (x − 5) = 0

⇒ (x − 5) (x + 1) = 0

∴ Either x − 5 = 0

⇒ x = 5

or

x + 1 = 0

⇒ x = −1

∴ Given set in roster (Tabular) form is  A₂ = {5, −1}