What is the common difference of the arithmetic sequence graphed below?

I think it’s -0.75. The x coordinate represents the term number so y would show the pattern which is -3.75, -4.5, -5.25, -6, -6.75, -7.5, -8.25, -9. To get to the next number, each term is being decreased by 0.75. Hope this helps :)

Arhombus is a quadrilateral.