I keep getting “Sum and product of roots” questions wrong in Quadratic Equations. What's the trap?
dropping the minus sign in −b/a.
The usual trap: dropping the minus sign in −b/a. How to avoid it: sum = −b/a, product = c/a — handy for building equations from roots. Go back to the definition — for ax²+bx+c=0, the roots add to −b/a and multiply to c/a (Vieta's relations).
Key point
Sum and product of roots
Common mistake
dropping the minus sign in −b/a.
Memory tip
sum = −b/a, product = c/a — handy for building equations from roots.
Tap to watch or see it right here — the app stays open (it only opens a quick search if nothing embeddable is found).