Question

Using complete sentences, explain which method you would use to solve the following system of equations and why. In your answer, include the solution to one of the variables and how you found it using the method you chose.
2x + y + z = -7
x - 3y + 4z = -14
x - 2y - 3z = -11

Answer 1

hmmm, math is not my thing
but i could do it

Answer 2

I am just so stuck anything would help

Answer 3

reduced-row echelon form can solve this. ill explain in a min

Answer 4

hmm

Answer 5

ok

Answer 6

sorry catmint but i've got nothing!

Answer 7

thanks for trying Ab590

Answer 8

no wonder you were stuck...

Answer 9

:)

Answer 10

what grade are you in, lol?

Answer 11

I'd use elimination, the easiest letter to eliminate is y

Doing so will leave you 2 equations in 2 unknowns.

and then select a letter to eliminate and proceed

Answer 12

sophomore

Answer 13

me too, im sophomore!

Answer 14

cool

Answer 15

maybe thats why i dun get it

Answer 16

@campbell_st I dont quite get how you make two equations

Answer 17

or how to use elimintation

Answer 18

ok... the elimination method is exactly that, you work on eliminating a letter from pairs of equations...

so you will go from 3 equations with 3 unknowns to 2 equations with 2 unknowns

so to eliminate y

triple the 1st equation and add it to the 2nd equation

6x + 3y + 3y = -21
x - 3y + 4z = -14
--------------------
7x +7z = -35 call this equation 4


then you double the 1st equation and add it to the 3rd equation

4x + 2y + 2z = -14
x -2y -3z = - 11
-------------------
5x - z = -25 call this equation 5

now look at which letter is easiest to eliminate... I'd say z... opposite signs

so multiply equation 5 by 7 and add equation 4

Answer 19

I am so confused

Answer 20

This is what I have 6x + 3y + 3z = -21
+x - 3y + 4z = -14
--------------------
7x + 7z = -35

4x + 2y + 2z = -14
+x -2y -3z = - 11
-------------------
5x - z = -25

Answer 21

35x= -25/35

Answer 22

Am I doing this right?

Answer 23

so confused. if you can tell

Answer 24

not quite

multiply equation 5 by 7 to eliminate z and add it to equation 4

7x + 7z = -35
35x - 7z = -175
------------------
42x = -210

now you can solve for x

Answer 25

ohhh my thanks. Will you be around to make sure I did it right?

Answer 26

well all the working above is correct... you just need to write up the process you used.

And you have the solution for 1 variable that you need to include in your answer...

Answer 27

this is what I wrote.
I'd use elimination, the easiest letter to eliminate is Y because it will leave me 2 equations in 2 unknowns.

6x + 3y + 3z = -21
+x - 3y + 4z = -14
--------------------
7x + 7z = -35

4x + 2y + 2z = -14
+x -2y -3z = - 11
-------------------
5x - z = -25

7x + 7z = -35
35x - 7z = -175
------------------
42x = -210

x= -5

Answer 28

is that right?

Answer 29

thanks for the help