Answer:
(x, y, z) = (3, -1, -3)
Step-by-step explanation:
The attached graph shows a solution that involves solving the system of equations that results from substituting for z. The second equation is used to write an expression for z that is substituted into the first and third equations.
One of the things we observe in this solution is that substituting into the first equation effectively eliminates x and z, so we learn immediately that y=-1.
That is, subtracting the second equation from the first gives ...
(2x +8y +z) -(2x +y +z) = (-5) -(2)
7y = -7
y = -1
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The solution by graphing is (x, y, z) = (3, -1, -3).
