math help!
posted by
Riana on
.
how to find the x intercept of d(x)=9x^24x+7

math help! 
Steve,
c'mon. It's just finding roots of a quadratic.
Since the discriminant is 164*9*7 < 0, there is no xintercept

math help! 
Riana,
yeah i know but how will you know when to use this discriminant formula ?