1) Find the range of values of k that give this equation no real roots.
a) (k + 1)x^2 + 4kx + 9 = 0

2) Show that x^2 + 2kx + 9 is >/ (more than or equal to) 0 for all real values of x, if k^2 /< (is less than or equal to) 9

Thank you very much - if you can show your workings to help me understand I'd be really grateful!

2. Originally Posted by heidithompson1990
1) Find the range of values of k that give this equation no real roots.
a) (k + 1)x^2 + 4kx + 9 = 0

2) Show that x^2 + 2kx + 9 is >/ (more than or equal to) 0 for all real values of x, if k^2 /< (is less than or equal to) 9

Thank you very much - if you can show your workings to help me understand I'd be really grateful!
a)
from the equation $(k + 1)x^2 + 4kx + 9 = 0$
you can get the value of a, b and c...
next step, you just verify that $b^2-4(a)(c)<0$

.....hope it help........