A constant is a fixed number. Conventional numbers are numbers whose numerical values can be determined and cannot be changed like the unknown X. The constants mentioned in the question generally refer to rational numbers (rational numbers generally include natural numbers, integers, fractions and decimals), and generally do not include irrational numbers, but sometimes the constants mentioned in the question can also be letters. For example, in the problem, A is a constant, so A cannot be regarded as a constant.

If you don't quite understand, you can use this noun to say a question in the supplementary question, and I will explain it to you specifically, so that you may understand it better.