Answer: f(n) = 0.9 × f(n − 1) + 10, f(0) = 175, n > 0
Step-by-step explanation:
Given: A store had 175 cell phones in the month of January.
Every month, 10% of the cell phones were sold and 10 new cell phones were stocked in the store.
Let n be the number of months
Then when n=0
f(0)=175
After first month , n=1
The number of cell phone in store=
Thus 

Similarly we can do till n months, we get
f(n)=0.9×f(n−1)+10, f(0) = 175, n > 0
Is this algebra one or two please mark me brainlist I need 1 more
Answer:
20 cm^2
Explanation:
Degree of area you want to find: 80
Length of radius: 9
Equation: 80/360 times 9
80/360= .2222222...
.2222222... times 9 = 20
So the answer is 20 cm^2