Question

7. If alpha and beta are the zeroes of quadratic polynomial x^2 -kx+15 such that (alpha + beta )^2 -2 *alpha* beta = 34 find k

Answer 1

Answer:

k=8

Step-by-step explanation:

alpha+beta=k

alpha*beta=15

Therefore

(alpha+beta)^2=k^2

2*alpha*beta=2*15=30

Therefore

(alpha+beta)^2-2*alpha*beta=34

k^2-30=34

k^2=34+30

k=√64

k=8