Answer:
10. -35/6
12. 52
Explanation:
A notation like - (-6) can be written as +6 ("two times minus is plus").
So your question 10. becomes:
(-19 + 20 + 34) / -6, which is more pleasant to the eye.
Further simplifying gives you 35 / -6 which you should write as -35/6.
The next question, same principle:
(-18 + 66 - 22) * 2 = 26 * 2 = 52