I would say 28 or 25 it's one of them I forgot it
If you show that the example is showing a false statement then you are disproving the example/problem.
You could re-write this to make it into an equation, you want to isolate the y, for a slope-intercept form. So you +8 to the other side; so it would be 7x+8=14y, then divide it by 14. And your equation would be y=4/7+x/2.