1. The problem is to understand the variable $x$ and its role in algebraic expressions. 2. In algebra, $x$ is commonly used as a variable representing an unknown value. 3. For example, in the equation $x + 2 = 5$, we solve for $x$ by subtracting 2 from both sides: $$x = 5 - 2$$ 4. Simplifying the right side gives: $$x = 3$$ 5. Thus, $x$ equals 3 in this example. 6. Variables like $x$ allow us to write general expressions and solve equations where the exact value is not initially known.