Hello, thank you for taking the time to post your question!
The “rate of change” means finding the slope, so I would put the equation into the form y = mx + b and then see what the value of “m” is
2y = 7x + 6
y = 7/2x + 3
so the rate of change here is 7/2 or 3.5
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)