3a. Solve 7x-5y=3

In order to find the general solution, set x=t and solve for y:

y=(7t-3)/5.

Thus the answer is:


x=t, y=(7t-3)/5


3b. Solve 3x1-5x2+4x3=7

As we did in the class, set x1=t, x2=s and solve for x3. The answer: 

				        x1=t,
				        x2=s,
				        x3=(7-3t+5s)/4