Question

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

Answer 1

z=5, so replace all z's with 5 is your first step.

Answer 2

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

Answer 3

Now you can simplify the first and last equations a bit

Answer 4

I'm really bad at simplifying.. x + 2y = -6?

Answer 5

I'm not sure how you got that... start with the first one:

2x - y + 5 = -4

subtract 5 on both sides

Answer 6

2x - y = -9

Answer 7

Much better. Now try simplifying the third equation:

-2x + 3y - 5 = -10

Answer 8

-2x + 3y = -5

Answer 9

Good. So now we have z=5, and these two:

2x - y = -9
-2x + 3y = -5

hopefully you kinda know how to use elimination, cos it'll make it very easy

Answer 10

Sorta. Substitution and elimination is what i'm learning right now.

Answer 11

Use elim.

Add the two equations together, vertically, like so

2x - y = -9
-2x + 3y = -5
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