Could anyone help me to answer these questions? Thank you very much!!!! :-)
1. Extract: "Computers are now essential in many areas of life- modern banking, retail, and information exchange among others."
Are there any word which is more appropriate than "areas of life" or "areas of life" sounds natural and there is no need to replace it with another phrase?
2. Extract: "some subject may be better taught using computers"
Why they use "using computers"? What is the subject of "using computers"? Could you help me to write the full sentence with the subject of "using computers"?

Question

Answer

"Computers are now essential in many disciplines..."
"Computers are now essential in many activities..."
"Computers are now essential in many professions..."
"Computers are now essential in many  realms of human activity..."
"Computers are now essential in many   pursuits..."
"Computers are now essential in many enterprises..."

"some subjectS may be better taught using computers"

(Some other ways of expressing the same idea):  
some subjectS may be better taught   with the use of computers
Some subjects may be better taught   by the implementation of computers into the classroom.
Rapid assimilation of knowledge can be implemented with the introduction of computers for student use.