Tartaglia solving the cubic -- in verse

     Mathematical historians now credit both Cardano and Tartaglia with the formula to solve cubic equations, referring to it as the "Cardano-Tartaglia Formula." Tartaglia is known for reporting solutions of three different forms of the cubic equation in a poem (1534).  Below we offer Boston poet Kellie Gutman's English translation of Tartaglia's verse, followed by the original Italian.

When X Cubed    by Niccolò Tartaglia (1500–1557)       (Englished by Kellie Gutman)

When x cubed’s summed with m times x and then   
  Set equal to some number, a relation    
  Is found where r less s will equal n.

Now multiply these terms. This combination
  rs will equal m thirds to the third;
  This gives us a quadratic situation,