One of these equations can be simplified to slope-intercept form: y = mx + b, where m is the slope and b is the y-intercept.
You have 2y = 14 - 2x and y = -x + 7. Divide 2y = 14 - 2x by 2 to get it in slope-intercept form.
(2y)/2 = (14 - 2x)/2
y = 7 - x
y = -x + 7
After dividing 2y = 14 - 2x by 2, we see that the two equations are the same; this means their graphs are the same. Since they share infinitely many points (being the same line), this system of equations has infinitely many solutions.
