Question

For what values of k are the roots of the quadratic equation $3x^2+2kx+27=0$ real and equal?

Answer 1

As we know, for reak equal roots we have

D = b²- 4ac = 0

here, b = 2k , a = 3 , c = 27

putting the values

= D = (2k)²- (4 x 3 x 27) = 0

0 = 4k² - 324

4k² = 324

k² = 324/4

k² = 81

k = 9