Ответ:

[tex] \frac{4x + 1}{12x {}^{4} y {}^{2} } - \frac{3y - 1}{9x {}^{3}y {}^{3} } [/tex]

[tex] \frac{3y(4x + 1)}{3y \times 12x {}^{4} y {}^{2} } - \frac{3y - 1}{9x {}^{3} y {}^{3} } [/tex]

[tex] \frac{3y(4x + 1)}{3y \times 12x {}^{4}y {}^{2} } - \frac{4x(3y - 1)}{4x \times 9x {}^{3}y {}^{3} } [/tex]

[tex] \frac{3y(4x + 1)}{36x {}^{4} y {}^{3} } - \frac{4x(3y - 1)}{36x {}^{4} y {}^{3} } [/tex]

[tex] \frac{3y(4x + 1) - 4x(3y - 1)}{36x {}^{4}y {}^{3} } [/tex]

[tex] \frac{12xy + 3y - 4x(3y - 1)}{36x {}^{4} y {}^{3} } [/tex]

[tex] \frac{12xy + 3y - 12xy + 4x}{36x {}^{4} y {}^{3} } [/tex]

[tex] \frac{3y + 4x}{36x {}^{4} y {}^{3} } [/tex]