\[(3x + 5)(4x - 5) - 2x(2,5 + 1,5x) =\]
\[= 12x^{2} - 15x + 20x - 25 - 5x - 3x^{2} =\]
\[= 9x^{2} - 25 = (3x - 5)(3x + 5).\]