Question

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

Answer 1

Question is worng.

-5 is a root of quadratic equation 2x^2+px-15=0

so, 2(-5)^2+p(-5)-15=0

50-5p-15=0

5p=35

p=7

again, put p=7 in second quadratic equation,

p(x^2+x)+k=0

7x^2+7x+k=0

a=7, b=7, c=k

D=b^2-4ac=0

7^2-4×7×k=0

49-28k=0

28k=49

k=7/4

hence, the value of k=1.75