Introduction to Analytic Number Theory
《Introduction to Analytic Number Theory》 · 第 110 页 · Section 5.3「Linear congruences」
Polynomial congruences can be studied in much the same way that polynomial equations are studied in algebra. Here, however, we deal with polynomials $f(x)$ with integer coefficients. An integer $x$ satisfying a polynomial congruence $f(x)=0\pmod m$ is called a solution of the congruence.