Answer this question pls!! (Will give Brainliest)

What is the common difference in the following arithmetic sequence? 7,3,-1,-5

In two or more complete sentences, formulate how to use technology to calculate the appropriate regression model for the given data. you are not required to find the model, just choose the appropriate regression and explain how to use the technology. (-5,,2.,0.8), (0,-0.5), (2,-1.3), (3,-0.8), (5,2)

Anyone know? will mark brainliest if you're correct!