Please answer, I’ll give brainliest

Use set builder notation to represent the following set: { -3, -2, -1, 0}

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

An archaeologist in turkey discovers a spear head that contains 53% of its original amount of c-14. find the age of the spear head to the nearest year. (5250 isn’t right)