First look for rational zeroes. If they exist they could be factors of ±15. Start with -3:
-54+135-66-15=0, so x+3 is a factor. Use synthetic division to find more zeroes:
-3 | 2 15 22 -15
2 -6 -27 | 15
2 9 -5 | 0 = 2x2+9x-5=(2x-1)(x+5)
The zeroes of the quadratic are: x=½ and -5. The three zeroes are -5, -3, ½.