Solve the system of equations
2x+y=3
x=2y-1

2x + y = 3
x = 2y - 1 
.
It looks like I could substitute the x=2y-1. Into 2x+y=3
2(2y-1)+y=3
4y-2+y=3
5y=5
y=1
x=2(1)-1
x=1

Cthe residual plot for model 1 has a non random pattern and is a good fit for the data

Yes, that is the correct formula. to solve this problem given the number of years, plug in the number of years for t and plug the whole thing into the