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Knowledge base
More explainers from the knowledge base. Each one names what you need to know first, works through the method, and says where it usually goes wrong.
Formula AlgebraDiscriminant Formula: What b² − 4ac Tells YouOne expression, evaluated before you solve anything, that tells you what kind of answer you are about to get.
Examples AlgebraQuadratic Formula Examples: 8 Worked ProblemsEight problems, each adding exactly one new difficulty to the one before it.
Mistakes Algebra5 Common Quadratic Formula MistakesFour of the five happen before any real calculating starts, which is why they are so easy to miss on the way back through.
Distinction AlgebraFactoring vs Quadratic Formula vs Completing the SquareThree methods, one answer. The discriminant decides which is fastest, and it takes a single line to find out.
Application AlgebraQuadratic Equations in Real Life: Where They Turn UpAnything under constant acceleration, and anything where two lengths multiply, produces a quadratic. That covers a surprising amount of the physical world.
Concept GraphingWhat Is Slope? Rise Over Run ExplainedSlope is one number that says two things: which way a line leans, and how sharply. Everything else about it follows from that.