Then apply the Rational Roots Test to obtain a list of possible whole-number and fractions zeroes. You should get:
. . . . .
Since whole numbers are easier, start trying whole-number solutions, such as -1 and +4, by synthetic division.
Once you've found one zero, you can plug the remaining quadratic into the Quadratic Formula to complete the solution.
If you get stuck, please reply showing all of your steps so far. Thank you!