Question

If roots of a quadratic equation 3y2+ ky+ 12= 0 are real and equal then
find the value of ‘k’

Answer 1

Answer:

12 or - 12

Step-by-step explanation:

For roots to be real and equal, discriminant of the equation must be 0. Discriminant of ax² + bx + c = 0 is b² - 4ac. In question,

a = 3, b = k, c = 12

Discriminant = 0

=> (k)² - 4(3)(12) = 0

=> k² - 144 = 0

=> k² = 144

=> k = √144

=> k = ± 12

Required values of k are ± 12.

Answer 2

Step-by-step explanation:

wrt Standard form ax² + bx + c ,

• a = 3
• b = k
• c = 12

We know for real and equal roots discriminant is 0 .

→ D = 0

→ b² - 4ac = 0

→ k² - 4(3)(12) = 0

→ k² - 144 = 0

→ k² = 144

→ k = √144

→ k = ±12