Question

write the set of values of k for which the quadratic equation 2x^2+kx-8=0 has real roots​

Answer 1

Answer:

the given quadratic equation 2x^2+kx-8=0

compare this equation with ax²+bx+c

a=2, b=k, c=-8

D= b² - 4ac..............(i)

put the values a=2, b=k, c=-8 in equation (i)

=(k)² - 4×2×(-8)

= k² - (-64)

= k²+64

the given equation will have real roots if D > 0

i.e., k²+64>0 which is true for all real values of k

(k)²> +(8)²

k> +8