Answer:
Line N is a vertical line with an undefined slope.
Step-by-step explanation:
When the points that line N passes through are graphed, they form a vertical line.
All vertical lines have an undefined slope.
We can also check if it's undefined by finding the slope.

The quotient would be undefined. You cannot divide by zero.
Hope this helps.
According to the 72 rule
72/rate=time
72÷9.6=7.5 years
Another way to solve by using the main equation
2300=1150(1+0.096/4)^4t
Solve for t
t=((log(2,300÷1,150)÷log(1+(0.096÷4))÷4))=7.31years
Hope it helps :-)