Question

If-5 is a root of the quadratic equation 2x2+px-15 =0and the quadratic equation p(x2+x)k=0 has equal roots find the value of k

Answer 1

Answer:

k = 7/4

Step-by-step explanation:

-5 is a root of 2x² + px - 15 = 0

then 2(-5)² + p(-5) - 15 = 0

50 - 5p - 15 = 0

5p = 35

p = 7

Now,

p(x² + x) + k = 0 ⇒7x² + 7x + k = 0 has equal roots

So, Discriminant = 0

7²-4(7)(k) = 0

28k = 49

k = 7/4