If \(y^{2} + xy - x = 0\), find \(\frac{\mathrm d y}{\mathrm d x}\).

A.

\(\frac{1 - y}{2y}\)

B.

\(\frac{1 - 2y}{x}\)

C.

\(\frac{1 - y}{x + 2y}\)

D.

\(\frac{1}{x + 2y}\)

Correct answer is C

Given \(y^{2} + xy - x = 0\)

Using the method of implicit differentiation, we have

\(2y\frac{\mathrm d y}{\mathrm d x} + x\frac{\mathrm d y}{\mathrm d x} + y - 1 = 0\)

\(\frac{\mathrm d y}{\mathrm d x}(2y + x) = 1 - y\)

\(\frac{\mathrm d y}{\mathrm d x} = \frac{1 - y}{x + 2y}\)