Discovery of explicit solution formulas for Polynomial eq. a₀xʲ+a₁xʲ⁻¹+…+aⱼ=0
j=2 Pythagoras (500 BC)
j=3 Girolamo Cardano (1545)
j=4 Lodovico Ferrari (1540)
j≥5 No general formula exists, Niels Abel (1824)

— Fermat's Library (@fermatslibrary) February 23, 2020