Question

The equation 3x² – 12x + (n – 5) = 0 has equal roots. Find the value of n.

Answer 1

3x² – 12x + (n – 5) = 0

Here a = 3, b = –12 and c = n – 5

Given equation has equal roots

Then D = 0

`\implies` b² – 4ac = 0

`\implies` [–12]² – 4(3)(n – 5) = 0

`\implies` 144 – 12n + 60 = 0

`\implies` –12n = –204

`\implies` n = `(-204)/(-12)` = 17