The subtraction theorem states that for all real numbers,

and

,

.
(To subtract, we can add the inverse.)
Thus, we can have the these two equivalent expressions.
Answer:
Angle QPM and Angle LMP are alternate interior I'm pretty sure, so I think B or second choice.
Let x be the number of days.
If Ashley posts 17 status updates each day, then after x days Ashley posts 17x status updates.
If Roberto posts 21 status updates each day, then after x days Roberto posts 21x status updates.
Part A. The combined number of posts for Ashley and Roberto after x days is:
17x+21x.
Part B. The difference between number of posts for Ashley and Roberto after x days is:
21x-17x.
We need to work out first the scale factor of the side length
Side MN correspond to the side JK
Side MN = 3.5 cm
Side JK = 14 cm
Scale factor = 14/3.5 = 4
Side OM correspond to side LJ
Side OM = 12 cm
Side LJ = 12 × 4 = 48 cm