eeveeabby9 eeveeabby9 08-04-2019 Mathematics contestada Select all of the following that are quadratic equations. 3 x^2 + 5 x - 7 = 0 x^3 - 2 x^2 + 1 = 0 2 x - 1 = 0 5 x^2 + 15 x = 0 6 x - 1 = 4 x + 7 x^2 - 4 x = 4 x + 7