Answer:
See below 
Explanation:
Use the roots given to make this :
 (x+3) (x-1/2) = 0 
 you can do the multiplication (if required) to get 
x^2 + 2.5x - 1.5 = 0  now you can multiply by 2 to get rid of the decimals
2x^2 + 5x - 3 = 0 
 All three are correct......pick the format you want ....