1. **State the problem:** We are given the equation $A + B = \frac{9}{2}$. We want to understand or solve this equation. 2. **Formula and rules:** This is a simple linear equation involving two variables $A$ and $B$. Without additional information or constraints, we cannot find unique values for $A$ and $B$, but we can express one variable in terms of the other. 3. **Intermediate work:** From the equation, $$A + B = \frac{9}{2}$$ we can isolate $A$ as: $$A = \frac{9}{2} - B$$ or isolate $B$ as: $$B = \frac{9}{2} - A$$ 4. **Explanation:** This means that for any value of $B$, $A$ must be $\frac{9}{2}$ minus that value, and vice versa. This represents a line in the $AB$-plane with intercepts at $A=\frac{9}{2}$ when $B=0$ and $B=\frac{9}{2}$ when $A=0$. **Final answer:** The equation $A + B = \frac{9}{2}$ can be rewritten as $A = \frac{9}{2} - B$ or $B = \frac{9}{2} - A$ to express one variable in terms of the other.