Can someone please help

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

Zoe placed colored blocks on a scale in science class. each block weighed 0.8 ounces. the total weight of all the colored blocks was 12.8 ounces. how many blocks did zoe place on the scale? write and solve an equation to find the answer.

What is the equation of a vertical line passing through the point (−5, −1)? y = −5 y = −1 x = −5 x = −1