Solving Quadratic Equations: Three Essential Methods
The quadratic formula is your reliable backup when other methods fail. For any equation in the form ax² + bx + c = 0, just plug the values into x = −b±√(b2−4ac)/2a.
Always write down your a, b, and c values first - this prevents silly mistakes. Remember to use brackets when substituting negative numbers, and don't forget that some quadratic equations have no real solutions at all.
Completing the square transforms your equation into the neat form x+p² + q. This method's brilliant for equations that don't give you nice integer answers. The key identities are x² + 2bx + c = x+b² - b² + c and x² - 2bx + c = x−b² - b² + c.
Factoring is often the quickest method when it works. Simply reverse the values in the brackets to make x = 0. For example, if you have x+6x−4 = 0, then x = -6 or x = 4.
Quick Tip: When you square root both sides of an equation, always use ± to show there are two possible answers!