6. What is the name of the symbol A? What does this symbol mean when
used before another symbol in an
equation?

"at symbol"

The at sign, "at symbol", is normally read aloud as "at"; it is also commonly called the at symbol or commercial at. It is used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets "at symbol" £2 per widget = £14), but it is now seen more widely in email addresses and social media platform handles.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

i really dont know but i will try okay.

so i think u would just add all them up and get your answer..