(ignore the question beneath it)

in 1990, for every person who lived in north america how many people lived in asia?
show your working

What is the answer to |-2x-5|-|-4+8| and x=7

Tracy solved the following problem. which of the statements is true? 9 ÷ 3 + 6 × 2 3 + 6 × 2 9 × 2 18 her answer is correct. her answer is incorrect. she should have multiplied before dividing. her answer is incorrect. she should have multiplied before adding. her answer is incorrect. she should have added before dividing.

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