<PRE><B>Question 670813</B>
Hint:


Solve for z in 2x +z = 7  to get z = -2x+7


Then  plug this into the second equation to get


2y -3z = -9


2y -3(-2x+7) = -9


2y + 6x - 21 = -9


2y + 6x = -9 + 21


2y + 6x = 12


6x + 2y = 12


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You now have the system


x-3y = 12
6x + 2y = 12


Use any method to solve this to find x and y. Then use x to find z.</PRE>