The x-axis occurs at y = 0, so the x-axis intercepts are found by letting y = 0. So yes the = 0 is important, no quadratic equation can be solved without it.

If you have a quadratic of the form then its solutions are

.

I'll leave you to do the research why this is so - hint, you complete the square.

Can you see that the solution depends on stuff under a square root? This is called thediscriminant, and is denoted by .

If there are exactly two solutions. (Why?)

If there is exactly one solution. (Why?)

If there are not any solutions. (Why?)

Can you see what a, b and c are in this equation? Find the discriminant and tell me what you can determine about the solutions.