Answer:
8a - 7
Explanation:
First, subtract 12a from 20a
20a - 12a
= 8a
Now, subtract -3 from -10.
Subtracting a negative number is the same as adding a positive number, so add 3 to -10.
-10 + 3
= -7
Put together 8a and -7
8a - 7
So, the simplified expression is 8a - 7