1. **State the problem:** We are given the formula $$h\frac{a+b}{2}$$ and need to find a formula for $a$ in terms of $h$, $b$, and the expression. 2. **Rewrite the expression:** The given expression is $$h\frac{a+b}{2} = \text{some value}$$. Let's denote this value as $V$ for clarity, so: $$V = h\frac{a+b}{2}$$ 3. **Isolate $a$:** Multiply both sides by 2 to eliminate the denominator: $$2V = h(a+b)$$ 4. **Divide both sides by $h$ to isolate $(a+b)$:** $$\frac{2V}{h} = a + b$$ 5. **Solve for $a$ by subtracting $b$ from both sides:** $$a = \frac{2V}{h} - b$$ 6. **Summary:** The formula for $a$ in terms of $h$, $b$, and $V$ (the value of the original expression) is: $$a = \frac{2V}{h} - b$$ This formula allows you to find $a$ if you know $h$, $b$, and the value of the expression $h\frac{a+b}{2}$.