Having troubles solving this system of equations. I would like to find our where I am going wrong.

Question

2x + 5y + z = -1

3x - 5y - z = 6

5x + y + 3z = 10

Answer 1

2x+5y+z=-1

3x-5y-z=6

5x+y+3z=10

add equations 1 and 2

5x=5

x=1

use equations 2 and 3 and replace the x's with 1

3-5y-z=6

5+y+3z=10

these become...

-5y-z=3

y+3z=5

multiply equation 3 by 5

5y+15z=25

-5y-z=3 eq2

5y+15z=25 eq3

add

14z=28

z=2

now you have x=1 and z=2

substitute into ant equation to get y

2+5y+2=-1

5y+4=-1

5y=--5

y=-1

x=1, y=-1, z=2 are the values for x, y and z