Question

solve the system
{ -5x-y=21
{ 3x-4y+5z=-8
{-3x-z=12

A. (-3,1,-1)
B.(21,-8,12)
C.(4,-1,0)
D.(-4,-1,0)

Answer 1

Well, let's see which numbers would work for each set.

Try plugging them in!
Let's start with plugging A into the first set.

\[-5(-3)-1=21\] Is this true?

Answer 2

no that's not true

Answer 3

Alright, so we can automatically eliminate A.

Let's plug B into equation 1.
Can you do this?

Answer 4

no you cant

Answer 5

so it would end up being D correct ?