What is the answer to number 1 question?

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

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

Simplify the rational expression. state any restrictions on the variable. t^2-4t-12 / t-8 the / is a fraction sign.