Question

If you were to use the substitution method to solve the following system, choose the new system of equations that would result if x was isolated in the second equation.

3x – 5y + z = 12
x + 6y – z = –4
2x – 5y – 2z = –8

4x + y = 8
–17y = 0

2x – 11y = 16
4x + 7y = –16

–23y + 4z = 24
–17y = 0

13y – 2z = 24
7y – 4z = 0

Answer 1

@rajathsbhat

Answer 2

what you have to do is re-arrange the second equation to get x (in terms of y & z). Once you've done that, substitute that 'x' into wherever there is x in the first & third equation. Simplify to get 2 equations in y & z.
Try it out!

Answer 3

x=-6y+z-4
so then...
3(-6y+z-4)-5y+z=12
-18y+3z-12-5y+z=12
-23y+4z=24

and...
2x–5y–2z=–8
2(-6y+z-4)-5y-2z=-8
-12y+2z-8-5y-2z=-8
-17y=0

Answer 4

C! :)

Answer 5

thanks @rajathsbhat

Answer 6

sure thing, yummy :)