To convert the rectangular equation x + y = 1 into parametric equations, one effective approach is to let x = t, which leads to y = 1 - t. The discussion highlights the need for three parametric equations, including z, which can be set as z = v. While there are numerous parametrizations available, the choice often depends on the specific application, such as simplifying integration for surface area calculations. Ultimately, the exact parametrization used does not affect the outcome of the double integral, as it will yield the same value regardless of the chosen method.