1. The problem asks to solve part (iv) similarly to the previous parts. Since the previous parts are not provided here, I will demonstrate a general approach to solving algebraic expressions or equations labeled as (iv). 2. Typically, part (iv) might involve solving an equation or simplifying an expression. The general formula or method depends on the problem type, such as solving linear equations, quadratic equations, or simplifying algebraic expressions. 3. For example, if part (iv) is solving an equation like $$ax^2 + bx + c = 0$$, we use the quadratic formula: $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ 4. Important rules: - Always simplify inside the square root first. - Check the discriminant $$\Delta = b^2 - 4ac$$ to determine the nature of roots. - Simplify the fraction fully. 5. Without the exact problem, I cannot provide specific intermediate steps. Please provide the exact expression or equation for part (iv) to solve it step-by-step. 6. If you provide the problem, I will solve it with detailed steps as requested.