Question

Find the values of k if the quadratic equation
$3 \times 2 - k \sqrt{3x + 40}$
has equal roots.

Answer 1

Hi ,

It is given that 3x² - k√3 x + 40 = 0 has equal

roots .

compare above quadratic equation with

ax² + bx + c = 0

a = 3 , b = - k√3 , c = 40

discreaminant = D = 0

b² - 4ac = 0

( - k√3 )² - 4 × 3 × 40 = 0

3k² - 480 = 0

3k² = 480

k² = 480/3

k² = 160

k = ± √ 160

k = ± 4√10

I hope this helps you.

:)