_+_+_= 30
Use only
1,3,5,7,9,11,13,15
You can repeat it

Answer
1 possible solution:
(5x7) in the first blank
(-3!) in the second blank
(-1) in the third blank
Step-by-step explanation:
(5x7) + -(3!) + -(1) 3! equals 3x2x1 or 6
35 + (-6) + (-1)