An earlier date for ``Cramer's rule'' (Q1969917)

The author justifies the claim made by the historian Carl Boyer that Cramer's rule for the solution of a set of linear equations was known to Colin MacLaurin (1698-1746) by 1729. His evidence comes from MacLaurin's Nachlass, which contains a transcription made that year of his `treatise of algebra, which was to appear in print posthumously, in 1748. Two folios are shown, stating the solution for three equations and indicating strategy for four equations. It is a pity that these folios were prepared for reproduction so carelessly, with the right hand edges cropped.