Please note: y = -x + 6 is NOT satisfied by (-3,8): 8 is NOT = to -(-3)+ 6.
Ensure that you have copied this problem down correctly.
Here I have changed the problem statement slightly: The slope-intercept form of the equation of a line that passes through point (–3, 8) is y = –x + 5
Re-writing this in point-slope form: y - 5 = -1(x-[-3] ).