Final answer:
The question contains fragments of algebraic expressions and equations, likely concerning simplification and possibly graphing. Due to ambiguity and lack of clarity, a direct answer cannot be provided without further details on the specific problem to be solved.
Step-by-step explanation:
The student's question seems to be involving algebra or pre-calculus, specifically regarding the simplification of algebraic expressions. Given the expressions and equations in the question details, the task at hand includes working with fractions, perfect squares, the quadratic formula, and possibly coordinate graphing. The fragments provided, such as 2 / 7 x + 3 / 5 y = x² + y² and dx²-y², suggest operations that deal with simplification, substitution, and graphing of equations. However, since the question lacks coherency and presents a mix of unrelated mathematical expressions, it is not possible to provide a direct answer or step-by-step solution. Ensuring clarity in the question is essential before a precise and correct answer can be formulated.