Yes, there is a difference!

If f(x) = 21x^{2} -79x + 30, then -f(x) = -21x^{2} + 79x - 30!

f(x) opens upward and goes to +∞as |x| goes to ∞, whereas -f(x) opens downward and goes to -≈ as |x| goes to ∞.

BUT, and this is where you are having trouble, if f(x)=0, then -f(x)=0 too, i.e. they have the same roots as you correctly observe.

I hope this helps!

David H.

Okay this make perfect sense, but how do I figure out which standard form it is when the roots -5/2 and 7 if the standard form is f(x)=(2x^2)-9x-35 or f(x)=(-2x^2)+9x+35?02/17/19