у ≠ -4; у ≠ 2

[tex] \frac{ \frac{3}{10} }{y - 4} = \frac{ \frac{7}{10} }{y - 2} \\ \\ \frac{3}{10(y + 4)} = \frac{7}{10(y - 2} \\ \\ 30(y - 2) = 70(y + 4) \\ \\ 30y - 60 = 70y + 280 \\ \\ 30y - 70y = 280 + 60 \\ \\ - 40y = 340 \\ \\ y = - \frac{17}{2} = - 8.5[/tex]