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| Question 1122204:  Find values of a, b, and c (if possible) such that the system of linear equations has a unique solution, no solution, and infinitely many solutions. (If not possible, enter IMPOSSIBLE.)
 x	 + 	y			 = 	4
 y	 + 	z	 = 	4
 x			 + 	z	 = 	4
 ax	 + 	by	 + 	cz	 = 	0
 
 Answer by ikleyn(52879)
      (Show Source): 
You can put this solution on YOUR website! . 
 
The  sub-system consisting of 3 (three) first equations has a unique solution x = y = z = 2.
When you add the fourth equation, it becomes
2a + 2b + 2c = 0,   or
a + b + c = 0.
Thus, 
    a)  if  a + b + c = 0,   then the system of 4 equations has a unique solution.
    b)  if a + b + c =/= 0,  then the system of 4 equations has no solution.
    c)  it is IMPOSSIBLE to this system to have infinitely many solutions.
Solved.
 
 
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