What are the square roots of 256?

a.
128 and –128

b.
15 and –15

c.
13 and –13

d.
16 and –16

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g