What part of speech is not appropriate in formal writing, but often used in daily conversation?

a. conjunction
b. adverb
c. preposition
d. interjection

Which of the following expressions is equal to 2x^2+8

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Kyle and elijah are planning a road trip to california. their car travels 3/4 of a mile per min if they did not stop driving, how many miles could kyle and elijah drive in a whole day? ? 1 day = 24 hours. plzzz i will give you 100 points