The roots of $x^2+3x-5=0$, correct to 2 decimal places, are: (√29 ≈ 5.3852)

$x=\frac{-3\pm \sqrt{9+20}}{2}=\frac{-3\pm 5.3852}{2}$, giving 1.1926 → 1.19 and −4.1926 → −4.19. Writing +b instead of −b in the numerator swaps the answers to 4.19 and −1.19; computing D as 9 − 20 wrongly suggests there are no real roots.