Question

2...The equation 9x2- kx+81=0 has equal roots find the value ofk k​

Answer 1

Step-by-step explanation:

The given equation if 9x2+kx+1=0

comparing with ax2+bx+c=0

here a=9, b=k , c=1

△ = b2−4ac

= k2−4(9)(1)

= k2−36

The roots are equal so △ must be zero

∴ = k2−36=0

= (x+6)(x−6)=0

=x+6=0 or x−6=0

∴ k=−6 or k=6

Answer 2

Answer:

Given equation, 9x²-kx+81=0

Here, a = 9, b = -k, c = 81

Now,

b² - 4ac = 0

(-k)²- - 4 .9 .81=0

k² - 2916=0

k² = 2916

k² = (54)²

k= ± 54

The value of k so that the equation 9x²-kx+81=0 has equal roots is 54 or -54.

Hope this helps