Final answer:
Without further context or definitions for V₂₁, it is not possible to determine the result of the expression (V₂ + V₂₁)⁴. Clarification on the notation is needed to provide a correct answer.
Step-by-step explanation:
The student is asking to find the result of the expression (V₂ + V₂₁)⁴. First, we must interpret V₂₁ in standard mathematical notation. Typically, index notation is not used for variables unless previously defined in a given context, such as a sequence or a matrix. Assuming that this is a typo without any additional context and that we are dealing with roots, V₂₁ might be intended to represent the square root of 21 (assuming V₂ is the square root of 2). However, given that there's no consensus on this interpretation from the provided context, and there is no standard V₂₁ notation in mathematics, we cannot confidently proceed with the calculations. To properly solve this problem, clarification on what is meant by V₂₁ is necessary, as well as any relevant context or definitions relating to this term.