BIS
Why put letters inside mathematics?
Algebra is a language for talking clearly about quantities we do not yet know.
The problem came before the symbol
People solved unknown-quantity problems long before modern x and y notation.
Variable · coefficient · expression · equation
Learn the language before memorising the trick.
CHECK YOURSELF
Can you explain the last idea in your own words without looking back?
An equation behaves like a balance
Any valid operation must preserve equality on both sides.
2x + 3 = 11
Subtract 3 from both sides, then divide both sides by 2. x = 4.
Unknowns are everywhere
Pricing, engineering, coding, budgeting and science all use known and unknown quantities.
Try it. Then prove it.
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