Răspuns
a) 1 * 2016 = 2016-1-2016+2 = -1+2 = 1
b) x * y = (x-1)(y-1)+1 = xy-x-y+1+1=xy-x-y+2
c) x * e = e * x = x
x * e = ex-x-e+2
e * x = ex-e-x+2
sunt comunitative si putem face:
x * e = x
ex-x-e+2=x
ex-e-2x+2=0
ex-e=2x-2
e(x-1)=2(x-1) [se simplifica x-1 cu x-1]
e = 2