Объяснение:

[tex]\left \{ {{3m - 5n = 0} \atop {3n + 4m = 29}} \right. \\\left \{ {{3m = 5n} \atop {3n + 4m = 29}} \right.\\\left \{ {{m = \frac{5n}{3} } \atop {3n + 4m = 29}} \right. \\\left \{ {{m = \frac{5n}{3} } \atop {3n + \frac{20n}{3} = 29 | *3}} \right. \\\\\left \{ {{m = \frac{5n}{3} } \atop {9n + 20n = 29 * 3}} \right. \\\\\left \{ {{m = \frac{5n}{3} } \atop {29n = 29 * 3}} \right. \\\\\left \{ {{m = \frac{5n}{3} } \atop {n = 3}} \right. \\\\\left \{ {{m = \frac{5 * 3}{3} } \atop {n = 3}} \right. \\\\[/tex]

Ответ:

m = 5

n = 3