Final answer:
To find the first partial derivatives of f(x, y) = (3x - 4y) / (3x + 4y), differentiate the numerator and denominator separately using the quotient rule. Then plug in the given coordinates to evaluate the derivatives at that point.
Step-by-step explanation:
To find the first partial derivatives of f(x, y) = (3x - 4y) / (3x + 4y), we need to use the quotient rule. The partial derivative with respect to x is found by differentiating the numerator and denominator separately and then applying the quotient rule. The partial derivative with respect to y is found in the same way. After finding the partial derivatives, plug in the coordinates (2, 4) to evaluate the derivatives at that point.