Question

if the quadratic equation 7(x2+x)+k = 0 has equal roots. find the value of k

Answer 1

Step-by-step explanation:

ANSWER

Since −5 is a root of the equation 2x2+px−15=0. Therefore,

2(−5)2−5p−15=0⇒p=7

Putting p=7 in p(x2+x)+k=0 we get

7x2+7x+k=0

Here ,a=7,b=7;c=k

This equation will have equal roots, if

Discriminant =b2−4ac=0 ⇒49−4×7×k=0⇒k=2849⇒k=47

Answer 2

Answer:

7/4=k

Step-by-step explanation:

7(x²+x)+k=0

=>7x²+7x+k=0

Here,

a=7 b=7 c=k

Since the equations has equal roots.

Therefore, discriminant(D)=0

D=0

b²-4ac=0

(7)²-4(7)(k)=0

49-28k=0

49=28k

49/28=k

7/4=k

Hope It Helps :)