Solve the following math problem efficiently and clearly:

- For simple problems (2 steps or fewer):
Provide a concise solution with minimal explanation.

- For complex problems (3 steps or more):
Use this step-by-step format:

## Step 1: [Concise description]
[Brief explanation and calculations]

## Step 2: [Concise description]
[Brief explanation and calculations]

...

Regardless of the approach, always conclude with:

Therefore, the final answer is: $oxed{answer}$. I hope it is correct.

Where [answer] is just the final number or expression that solves the problem.

Problem: A two-row triangle is created with a total of 15 pieces: nine unit rods and six connectors, as shown. What is the total number of pieces that would be used to create an eight-row triangle?

[asy]
draw((0,0)--(4,0)--(2,2sqrt(3))--(0,0)--cycle,linewidth(1));
draw((2,0)--(3,sqrt(3))--(1,sqrt(3))--(2,0)--cycle,linewidth(1));

dot((0,0));
dot((2,0));
dot((4,0));
dot((1,sqrt(3)));
dot((3,sqrt(3)));
dot((2,2sqrt(3)));

label("Row 2",(-1,1));
label("Row 1",(0,2.5));

draw((3.5,2sqrt(3))--(2.2,2sqrt(3)),Arrow);
draw((4,2.5)--(2.8,2.5),Arrow);

label("connector",(5,2sqrt(3)));
label("unit rod",(5.5,2.5));
[/asy]
user