Question

In the solution to this system, what is the value of y?

x+y+z=1

2x+y-z=8

x-y+z=15

y=______

The solution is ?

Answer 1

solve by linear combination

add 1st and 2nd equation together to get

3x+2y=9

add 2nd and 3rd equation together to get

3x=23

divide by 3

x=23/3

sub into other one

3x+2y=9

23+2y=9

2y=-14

y=-7

Answer 2

y=-7

hope this helps you