Question

find the value of k for quadratic equation kxsquare+(2k+4)x+9 so that they have two equal root​

Answer 1

Answer:

write the discriminant =0 and.solve

Answer 2

Therefore the value k is = 4 or 1.

Step-by-step explanation:

Given quadratic equation is

$k x^2+(2k+4)x+9=0$

If the equation $ax^2+bx+c=0$ has two equal roots. Then the value of $b^2-4ac$ will be zero.

Here a=k

b=(2k+4)

c=9

Therefore $b^2-4ac$=0

          $\Rightarrow (2k+4)^2-4\times k\times 9=0$    

          $\Rightarrow 4k^2+16k+16 - 36k =0$

          $\Rightarrow 4k^2-20k+16=0$

          $\Rightarrow 4(k^2-5k+4)=0$

          $\Rightarrow k^2-5k+4=0$

          $\Rightarrow k^2-4k-k+4=0$

          $\Rightarrow k(k-4)-1(k-4)=0$

          $\Rightarrow (k-4)(k-1)=0$

          $\Rightarrow k= 4,1$

Therefore the value k is = 4 or 1.