Question

Find the value(s) of 'a' for which the quadratic equation x² – ax + 1 = 0 has real and equal roots.

Answer 1

Given quadratic equation is x² – ax + 1 = 0

On comparing it with ax² + bx + c = 0, we get

a = 1, b = –a and c = 1

For real and equal roots, D = 0

i.e. b² – 4ac = 0

⇒ (–a)² – 4(1)(1) = 0

⇒ a² – 4 = 0

⇒ a² = 4

⇒ a = ±2