Question

Solve the system by substitution.
2x-y+z=-4
z=5
-2x+3y-z=-10


a.) (-8, 7, 5)
b.) (–8, –7, 5)
c.) (8, –7, 5)
d.)(–8, –7, –5)

Answer 1

@amorfide Please help.. I can't do this

Answer 2

Still there?

Answer 3

Ok. This is actually simple. We already know Z = 5. So substitute that into any of the two remaining equations. Ill go with 2x - y + 2 = -4.

Answer 4

I mean. 2x - y + z = -4 Sorry about that.

Answer 5

So now we have 2x -

Answer 6

2x - y + 5 = -4 --> -y = -2x -5 - 4 or otherwise y = 2x +5 + 4

Answer 7

Now substitute that into -2x + 3y - z = -10. So -2x + 3(2x + 5 + 4) - 5 = -10 Now. Itll end up being -2x + 6x + 15 + 12 - 5 = -10. Which will then become 4x + 15 + 12 - 5 = -10. Hopefully you know what to do after that. x = -8.

Answer 8

So. We have x = -8, and z = 5. Substitute into any equation. Ill use 2x - y + z = -4. Which will be -16 - y + 5 = -4. --> y = -16 + 5 + 4. SO Y = -7. X = -8 and Z = 5. Hope you get it now. :)

Answer 9

-waiting patiently for my best answer medal- lol