add solution to Exercise 7.3-2.

Included are the following 2 files:

	7.3-2.pdf
	7.3-2.tm

Thank you!
							Lawrence X. Amlord
							  Aug 2nd, 2014
							  Xi'an, China
add solution to Exercise 7.4-1.

Included are the following 2 files:

	7.4-1.pdf
	7.4-1.tm

Thank you!
							Lawrence X. Amlord
							  Aug 2nd, 2014
							  Xi'an, China