y=640(1.073)^3

To solve this equation, follow these steps:

1. Start by simplifying the expression inside the parentheses:
1.073^3 = 1.236196857

2. Substitute this value back into the equation:
y = 640 * 1.236196857

3. Calculate the product:
y = 790.3480214

Therefore, y = 790.3480214.