Question

If one root of the equation 2x^2+px-5=0 is -5 and the quadratic equation P(x^2-a)+k=0 has equal roots find the value of k.

Answer 1

Answer:

One zero is (-5)

f(x)=2x^2+px-5=0

f(-5)=2(-5)^2+p+(-5)-5

0=50-5p-5

5p=45

.:p=9

P(x^2-x)+k=0

Px^2-px+k=0

.:equation:-

9x^2-9x+k=0

As zeroes are equal

.: D=0

D=b^2-4ac

0=(9)^2-4(9k)

0=81-32k

32k=81

.: k=81/32