Suppose $f: \R \to \R $ is a first-order polynomial. In other words, there are coefficients $\alpha , \beta \in \R $, $\alpha \neq 0$, so that $f(x) = \alpha x + \beta $ for every $x \in \R $. Then $f(x) = 0$ is a first degree equation.
We write
\[
\alpha x + \beta = 0
\] \[
x + (\beta /\alpha ) = 0
\]
Given a real number $a \in \R $, suppose we
want to find $x \in \R $ so that
\[
x + a = 0
\]