median
don steward
mathematics teaching 10 ~ 16

Wednesday, 16 February 2011

solving un-nice quadratics

several U.S. blogs (James Tanton in particular) advocate multiplying by 4 in order to more easily complete the square when the x-coefficient is an odd number:


which seems a helpful technique






my preference, as mentioned previously, is to transform the equation using a difference of two squares technique (as advocated by David Wells):


this preference is because it's straightforward plus I quite like students to be able to mentally square something.5

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