Question

1x+1=x+1, 1x+-1=x+1, -1+-1=x+1, -1x+1=x+1. which one has exactly one solution

Answer 1

1x+1=x+1 = True

1x+-1=x+1 = False

-1+-1=x+1 x= -3

-1x+1=x+1 = x = 0