equational

equation +‎ -al

equational (not comparable)

1. Of, pertaining to, or constructed using equations
   • 1696, Samuel Jeake Senior, Λογιστολογία, or Arithmetick Surveighed and Reviewed: in Four Books, London: […] J. R. and J. D. for Walter Kettilby […], and Richard Mount […], page 8:

     Again Homogeneal Numbers may hold community in Special Denominations, being considered in the Ratio, or Proportion of Equality; and ſuch are called Æquations, and by ſome Algebra; So Numbers Æquational are Numbers equal one to the other, though the Denominations of ſuch Numbers are different, as one Square ſhall be Equal to Three Roots, if the Root be Three;