Ответ:

x=35/32

y=7/8

[tex]3y + 4x = 7 \\ 4x - 5y =0 \\ \ \\ \\4x = 7 - 3y \\ 4x - 5y = 0 \\ \\ \\7 - 3y - 5y = 0 \\ 7 - 8y = 0 \\ 8y = 7 \\ y = \frac{7}{8} \\ \\ \\4x - 5 \times \frac{7}{8} = 0 \\ x = \frac{35}{32} [/tex]