Answer:
-1.47, 1.14 to 2 decimal places.
Explanation:
3x^2 + x - 5 = 0
3(x^2 + 1/3x) - 5 = 0
Completing the square on the expression in the parentheses:
3[(x + 1/6)^2 - 1/36) - 5 = 0
3(x + 1/6)^2 - 1/12 - 5 = 0
(x + 1/6)^2 = 61/12 / 3
(x + 1/6)^2 = 61/36
(x + 1/6) = +/-√61 / 6
x = -1/6 +/- √61 / 6
x = 1.135, -1.468