check my work please? :)

solve the system by substitution

2x - y + z = -4
z = 5
-2x + 3y - z = -10

I plugged it in and got (-8, 7, 5) is that correct?

Question

check my work please? :)

solve the system by substitution

 2x - y + z = -4 
z = 5
-2x + 3y - z = -10

I plugged it in and got (-8, 7, 5) is that correct?

anonymous · Answer

NEVER MIND I DID IT WRONG UGH I FORGOT THE NEGATIVES. one sec let me figure this out in the mean time please help!

anonymous · Answer

okay I changed it i do think it's (-8, -7, 5) 
because 2(-8) - (-7) + 5 = -4
-16 - (-7) + 5 = -4
-9 + 5 = -4
-4 = -4

anonymous · Answer

@Hero

hero · Answer

Just remember to test each equation. Just because it works for one doesn't mean it works for all.

anonymous · Answer

I did I plugged it into the other equation and got -10 = -10