Question

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

Answer 1

Answer:

The first quadratic equation given is :-

Also,

one root of the equation is (-5)

So,

According to remainder theorem :-

P(-5)=0

So,

Thus,

Value of p is 7.

Now ,

The second quadratic equation is

The equation has equal roots.

This means that :-

D=0

So,

D = b²-4ac

So,

Value of D is equal to :-

So,

Value of k is 7/4.