As a formula, you're saying 4*(n-7)=32
This solves to n-7 = 8, so n=15
The last one y=2x-5 if you plug the points into the x and y values you can see this equation works for both points.
Subtract the second equation from the first equation.
x = -1
Plug -1 back in to either equation and solve for y.
3(-1) + y =-10
-3 + y = -10
Add 3 to both sides
y = -7
CHECK
3(-1) -7 = -10
2(-1) -7 = -9
(-1, -7)
Here, number of periods (years), n=5
Annual interest rate, i=0.05 (compounded yearly)
Present value/deposit, P=100
Future value of deposit = P(1+i)^n=100(1.05^5)=127.63 (to the nearest cent)
Answer: After 5 annual interest payments, Bob will have 127.63 in his account.
