3.what would be the best place to build an optical telescope?

4.a measure of the amount of light given off by a star is its?

5.the first artificial satellite to orbit the earth was?

I can help you with question 5.  The first artificial satellite to orbit the Earth was called Sputnik I, launched by the (then) Soviet Union in 1957.

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)