Why is venus known as the morning star and the evening star

It can be seen before sunrise or just after sunset as a bright morning or evening star. 

Venus's orbit is in Earth's orbit. 

When venus is on one side of sun...it brightens into view when the sun sets...therefore the evening star.

Venus on the other side of the sunyou will see it as the morning star a few hours before the sunrise

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)