Algebra
The moves that turn an unknown into a known — and why each one is allowed.
Key ideas
An equation is a balance
Whatever you do to one side, you must do to the other. Every legal move — adding, dividing, factoring — keeps the two sides equal while making x easier to see.
Factoring is un-multiplying
x² + 5x + 6 = (x + 2)(x + 3) is just multiplication run backwards. If a product equals zero, one of its factors must be zero — that single fact turns quadratics into two easy equations.
Slope is a rate
In y = mx + b, m tells you how much y changes for each step of x, and b tells you where the line starts. Read them and you can sketch any line without plotting points.
Flashcards
Quick quiz
1 / 5
What is x in 3x − 7 = 11?
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