ta có:
`x : 2` = `y : (-5)` => `x/2` = `y/-5`
Gọi `x/2` = `y/-5` = `k`
=> x `= 2k ; y = -5k`
=> x `- y = 2k - (-5k) = 7`
=> `2k + 5k = 7`
=> `(2+5)k = 7`
=> `7k = 7`
=> `k = 1`
=> `x/2` = `1` => x = `2`
=> `y/-5` = `1` => `y = -5`
VẬY .....................
XIN HAY NHẤT Ạ