`{x-5}/{x+7} = {x-2}/{x+3}`
`=> (x-5)(x+3) = (x+7)(x-2)`
`=> x^2 + 3x - 5x - 15 = x^2 - 2x + 7x - 14`
`=> x^2 - 2x - 15 = x^2 + 5x - 14`
`=> x^2 - 2x -15 - x^2 - 5x +14 =0`
`=> (x^2-x^2) + (-2x-5x) + (-15+14) =0`
`=> -7x -1 =0`
`=> -7x = 1`
`=> x ={-1}/7`
Vậy `x = {-1}/7`