(7, -2).
Reflection will remain the same distance with the symmetrical line.
The expressions 100×10 and the more complicated
(100 - 4a)(10 + a)
are calculating annual (expected) revenue. In 100×10 the 100 is the number of decks and the 10 is the price per deck. In (100 - 4a)(10 + a) the 100-4a is the number of decks and the 10+a is the price per deck. So a must be the amount the price increases.
Answer: amount of price increase, last choice
a relation that is not a function
1 year = 12 months
$1200/2 years
$1200/ 24 months
$50/1 month
add the interest which would be 5% of 50
50×0.05=2.5
50+2.5=52.5
She would pay you $52.50 per month