Algebra · Formulae & rearranging
Chapter 1 · 3
The idea
Changing the subject when it appears twice
Why a subject that appears twice must be collected and FACTORISED out, how clearing a fraction first exposes both copies, and the four-step routine that untangles any of these.
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Algebra · Formulae & rearranging
Changing the subject when it appears twice
Why a subject that appears twice must be collected and FACTORISED out, how clearing a fraction first exposes both copies, and the four-step routine that untangles any of these.
Why it works
Peeling can't finish this one
Make the subject of . This is top-grade rearranging, and the reason is one detail: the wanted letter appears twice. Try the usual one-step peeling and watch it fail — however you move things around, an stays stranded on each side, forever. The escape is factorising: collect both -terms into ONE times a bracket, and then a single division sets it free. That formula is our running example, and the routine below untangles it completely.Keep reading — free
The rest of the explanation, plus 2 worked examples you step through move by move.
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