I am looking for help with this general accounting question using proper accounting standards.

Given the following costs and machine hours for Brighton Manufacturing, use the high-low method to calculate Brighton's variable maintenance costs per machine hour: July: $14,400 at 18,000 machine hours August: $16,200 at 21,000 machine hours September: $13,800 at 17,000 machine hours Question: What is Brighton Manufacturing's variable maintenance cost per machine hour