2: x2 + x -16 = 0 The quadratic formula is X = -b . using ax2 + bx + c = o. We can determine that a = 1, b = 1, and c = -16. Once you plug in the values you are left with X = -1 / 2 (1) This simplifies to X = -1 When you simplify further you get X = -1 8.06 / 2 Therefore you would do X = -1 +8.06 /2 or X = 3.53 and X = -1 - 8.06 /2 or X = -4.53