| 4x	+ 8y	+ 7z	+ 3cw		= 3b
<   x	+ 2y	+ 2z	+ cw		= b	(c and b are real parameters)
 | 2x	+ 4y	+ 2z	+ (c-1)w	= b

For which values of b and c:
(i) there is no solution?
(ii) there is a single solution? what is it?
(iii) infinite solution? Write down the general solution