Respuesta :

Subtract 1 to put the equation in general form (also called Standard Form in the US).
  2x² + 5x - 1 = 0

The value of b²-4ac is found by substituting the values of a, b, c in that expression. In this equation,
  a=2
  b=5
  c=-1

b²-4ac = 5²-4(2)(-1) = 25+8
b²-4ac = 33