1540 Ferrari 1522-1565 secretary/student of Cardano, solved quartic equations.

1545 Cardano 1501-1576 in Ars Magna gave the formula that solves any cubic equation based on Tartaglia's work and the formula for quartics discovered by Ferrari.

1572 Bombelli 1526-1572 in Algebra gave the rules for calculating with complex numbers. Diophantus problems.