Solve the following system of equations?

x + 3y - z = 2

x - 2y + 3z = 7

x + 2y - 5z = - 21

a) (2, 3, 5)

b) (-2, 3, 5)

c) (2, - 3, 5)

d) (2, - 3, 5)

1x + 3y - 1z = 2 ⇒ 1x + 3y - 1z = 2

1x - 2y + 3z = 7 ⇒ 1x - 2y + 3z = 7

1x + 2y - 5z = - 21 5y - 4z = - 5

5y - 4z = - 5 ⇒ - 20y + 16z = 20

1x + 3y - 1z = 2 - 4y + 8z = - 28 ⇒ - 20y - 40z = - 140 1x - 2y + 3z = 7 ⇒ 1x - 2y + 3z = 7 - 24z = - 120

1x + 2y - 5z = - 21 ⇒ 1x + 2y - 5z = - 21 - 24 - 24

-4y + 8z = - 28 z = 5

5y - 4 (5) = - 5

5y - 20 = - 5

+20 + 20

5y = 15

5 5

y = 3

x + 3 (3) - 5 = 2

x + 9 - 5 = 2

x + 4 = 2

-4 - 4

x = - 2

(x, y, z) = (-2, 3, 5)

The solution to the answer is B. (-2, 3, 5).