Question

Which ordered triple is a solution of this system?

2x + y - z = 7
-x - 2y + 4z = -15
x + 2y - 5z = 17

a) (3, 1, 0)
b) (1, 3, -2)
c) (2, 5, 2)
d) (-2, 6, -5)

Answer 1

b) (1, 3, -2)

Explanation:

A suitable calculator can give you the answer to this right away. Or, you can try the answer choices in the equations to see which works.

The answer choice that works is choice B.

2·1 +3 -(-2) = 7

-1 -2(3) +4(-2) = -15

1 +2(3) -5(-2) = 17