# The Sum and Product of Roots Theorem

From the quadratic formula, we know that the numbers $latex r_1$ and $latex r_2$ are the roots of the quadratic equation $latex ax^2 + bx +c =0$ where $latex a \neq 0$ if and only if

$latex r_1 + r_2 = -\frac{b}{a}$

and

$latex r_1r_2 = \frac{c}{a}$.  Continue reading

The quadratic formula is a formula in getting the roots of the quadratic equation $latex ax^2 + bx + c = 0$, where $latex a$, $latex b$ and $latex c$ are real numbers and $latex a \neq 0$. The quadratic formula is a generalization of completing the square, and it is usually used as a calculation strategy if a quadratic equation is not factorable.
In the graph of the quadratic function $latex f(x) = ax^2 + bx + c$, the values of $latex x$ in $latex ax^2 + bx + c = 0$, are the coordinates of $latex x$ where the curve pass through.