[tex]\frac{9x-5y}{2x+3y} = \frac{2}{21}[/tex]
(9x-5y)*21=(2x+3y)*2
189x-105y=4x+6y
189x-4x=105y+6y
185x=111y se imparte la 37
5x=3y => => x=3 si y=5
Verificam:
[tex]\frac{9*3-5*5}{2*3+3*5} = \frac{2}{21}[/tex] ok
=>[tex] \frac{8x-3y}{5x+9y} = \frac{8*3-3*5}{5*3+9*5}= \frac{24-15}{15+45} = \frac{9}{60} = \frac{3}{20} [/tex]