Solving Equations by Factoring
If two numbers have a product of 0, then at least one of the numbers
must be 0. That is, if ab = 0, then either a = 0 or b = 0.
An equation that can be written in the form
ax2 + bx + c = 0,
where a ≠ 0, is a quadratic equation. This form is called standard form.