I know this is a stupid question but, I posted this thread up not long a go Function derivatives. I'm trying to replicate this question. However, I can't seem to work out how I got the value $-2$ and $3$ from the quadratic formula. I've tried and tried to use the template, however each time im getting different values to the ones I got when I successfully done it. The formula is $6x^2-6x-36\dots$
[Math] quadratic formula – getting wrong values
quadratics
Best Answer
No need to use the quadratic formula, but of course you can do so to yield the same roots:
$$\begin{align} 6x^2 - 6x - 36 = 0 & \iff 6(x^2 - x - 6) = 0 \\ \\ & \iff x^2 - x - 6 = 0\\ \\ & \iff (x+2)(x - 3)= 0 \\ \\ &\iff x = -2 \;\text{or}\; x = 3\end{align}$$