Question

If the difference of the roots of the equation x² – bx + c = 0 is 1, then:

Options

• b² – 4c + 1 = 0

• b² + 4c = 0

• b² – 4c – 1 = 0

• b² – 4c = 0

Answer 1

b² – 4c – 1 = 0

Explanation:

Let roots are α and β.

⇒ α – β = 1

∵ (α – β)² = (α + β)² – 4αβ

⇒ 1 = b² – 4c

⇒ b² – 4c – 1 = 0