Answer: 30, -36, 42
Step-by-step explanation:
So basically the pattern is just the next number that is a multiple of six, but every other number is negative. 6 is 6 times 1, -12 is 6 times -2, 18 is 6 times 3, -24 is 6 times -4, 30 is 6 times 5, -36 is 6 times -6, and 42 is 6 times 7