Answer:
(a)
dependent
(b)
x = -3t - 12
y = -5t - 16
z = t
Step-by-step explanation:
2x - 3y - 9z = 24 Eq. 1
x + 3z = -12 Eq. 2
-3x + y - 4z = 20 Eq. 3
2x - 3y - 9z = 24
(+) -9x + 3y - 12x = 60 3 * Eq. 3
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-7x -21z = 84 Eq. 4
7x + 21z = -84 7 * Eq. 2
(+) -7x - 21z = 84 Eq. 4
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0 = 0
(a) The system is dependent.
(b)
z = t
x + 3z = -12 Eq. 2
x + 3t = -12
x = -3t - 12
2x - 3y - 9z = 24 Eq. 1
2(-3t - 12) - 3y - 9t = 24
-6t - 24 - 3y - 9t = 24
-3y - 15t = 48
-y - 5t = 16
-y = 5t + 16
y = -5t - 16
x = -3t - 12
y = -5t - 16
z = t
