Question

(1) If the roots of quadratic equation 2x2 + 6x +k=0 are real and
equal then find the value of k.​

Answer 1

Answer:

K = 9 / 2

Step-by-step explanation:

Roots on an equation can be equal iff it's discriminant is 0.

On comparing the given equation( 2x^2 - 6x + k = 0 ) with ax^2 + bx + c = 0 : -

Coefficient of x^2 = 2

Coefficient of x = - 6

Constant term c = k

Discriminant of a quadratic equation is difined by :

∆ = b^2 - 4ac

= ( coefficient of x )^2 - 4( coefficient of x^2 )( constant term )

= ( - 6 )^2 - 4( 2 )( k )

= 36 - 8k

Since discriminant is 0 : 36 - 8k = 0 = > 36 / 8 = k = > 9 / 2 = k

Hence the required value of k is 9 / 2.

Answer 2

$\sqrt{} | b ^{2} - 4ac$