Answer:
1a) the GCF of 6 and 9 is 3.
1b) -9
Step-by-step explanation:
1a) The greatest commons factor is the greatest number that divides two numbers. 3 is the largest number that goes into both 9 and 6 evenly. Therefore, 3 is the GCF.
1b) 6*3=18 and 9*3=27
18-27=-9