Using the formula (n -2) x 180* we find that there is 4 sides (n) and in put it and simplify to make (2)x180*. From there we calculate there is 360* in this polygon, and subtract the degrees already provided. 360-210=150
X cannot equal itself minus 5, in the same way if we replace it by let's say, 6...
6 does not equal 6-5 (1)........ and by the way in this specific equation 6 is just an example it does not matter what you replace it with, x can never = x-5
