Answer:
-5.5 and 0.4 (first option in your list)
Step-by-step explanation:
Please see attached image where we have graphed the expression [tex]y=6x^2+31x\\[/tex] and the expression [tex]y=12[/tex] and looked for the two points of intersection of the parabola (representing the first expression) with the horizontal line (second expression)
From the graphing we extract that one solution for "x" is approximately -5.5, and the other one around 0.36, which can be rounded to one decimal to: 0.4. then the closest solution is that one shown as the first option in your list.
