Question

Choose all of the following which lie on the graph of x + 2y - z = 8.

A)

(5, 2, 13)


B)

(1, 2, 0)


C)

(6, -2, -6)


D)

(-3, -1, -8)

Answer 1

As an example, let's look at B:  x=1, y=2, z=0.

Evaluating the left side of the given expression in x, y and z, we get

x + 2y - z = 8  =>  1 + 2(2) - 0 = 5, which does not equal  8.  So B is not a solution.  

Please check out the other possible solutions. Which set {x, y, z} makes the given equation true?