Mark M. answered 08/30/18
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Retired math prof. Very extensive Precalculus tutoring experience.
Rearrange: x + z = 6
2y + 6z = 36
4x - y + z = 6
Multiply equation 1 by -4 and add to equation 3:
x + z = 6
2y + 6z = 36
-y - 3z = -18
Multiply equation 2 by 1/2 and add to equation 3:
x + z = 6
2y + 6z = 36
0 = 0
So, x = 6 - z
y = 18 - 3z
z = any real number, t
Solution set: {(6-t, 18-3t, t) l t = any real number}
= {t(-1, -3, 1) + (6, 18, 0) l t = any real number}
Selena H.
08/30/18