Lets pick a random number, like 50. Lets decrease and increase it by 50%. After the decrease, you will get 25, but when you increase it by 50%, it's only 37.5. No, because when you decrease it, you have a smaller base, so it increases less than it decreases. 50% of 100 is 50, but 50% of 50 is 25. You can see there is a significant difference.
1)
answer
A. PQR = PSQ = QSR
2)
answer
B. MNO = MOP = PNO
For this case we have that by definition, the Greatest Common Factor (GCF) is the largest factor that 2 numbers have in common.
So, we have the following expressions:

We look for the positive integers that divide to 35 and 42 without leaving residue:
42: 1,2,3,6,7,14,21
35: 1,5,7
Thus, the GCF of 42 and 35 is 7
Then, the GCF of the three expressions is:

Answer:
