Question

Sum of the roots of a quadratic equation is double their product. Find k if equation is x2-4kx +k+3=0

Answer 1

Hi ,

Compare x² - 4kx + ( k + 3 ) = 0 with

ax² + bx + c = 0 we get ,

a = 1 ,

b = - 4k ,

c = ( k + 3 ),

1 ) sum of the Roots = - b/a

= - ( - 4k )/1

= 4k

2 ) product of the roots = c/a

= ( k + 3 )/1

= k + 3

according to the problem given ,

4k = 2( k + 3 )

4k = 2k + 6

4k - 2k = 6

2k = 6

k = 6/2

k = 3

I hope this helps you.

: )

Answer 2

Hii friend,

X²-4KX+K+3

Here,

A = 1 , B = -4K and C = K+3

We know that,

Sum of zeros = -B/A => -(-4K/1) = 4K/1

And,

Product of zeros = C/A => K+3/1 => K+3

According to question,

Sum of zeros = 2 × Product of zerso

4K/1 = 2 × K+3/1

=> 4K/1 = 2K+6/1

=> 4K-2K = 6

=> 2K = 6

=> K = 6/2 => 3


Hence,

The Value of K is 3.



HOPE IT WILL HELP YOU..... :-)