When solving the unary linear equation, we first think that the denominator is not 0, so the set A = {x | ax+b=0} has at least one element, that is, the unary linear equation ax+b=0 has at least one solution, so when a=0, b must be 0, and when a is not equal to 0, the value of b is arbitrary, which is the set A = {x | ax+.