Answer: d. (17, 20)
Step-by-step explanation:
We have the following system of equations:
(1)
(2)
Isolating 
from (1):
(3)
Substituting (3) in (2):
(4)
Isolating 
:
(5)
(6)
(7)
Substituting (7) in (1):
(8)
Isolating :
(9)
Hence, the correct option is d. (17, 20)
A geometric sequence is one that involves addition or subtraction. One example would be "In an auditorium, the 1st row has 25 seats. The 2nd has 30. The 3rd has 35. How many does the 4th have? Take the formula, x + 5. All you do is simply add 5.
An arithmetic sequence is one that involves multiplication or division. For example, "Jon receives 5 dollars each week. If he waits for 5 months, how much money will he have? Honestly, all you have to do is think about the formula. x * 5. x would be the number of weeks.
I know my answer is not as good as the verified one, but it is simpler and easier to understand. I apologize if it isn't good enough.
80/4=20
20x7=140
7 shoes = 140
lets assume one number is x
then 2nd number will be 5x-2
so product is 120
x (5x-2) = 120
5x^2 - 2x = 120
so answer is last option
