(3x+5)(4x-5)-2x(2.5+1.5x)
= 12x^2 - 15x + 20x - 25 - 5 - 3x
= 12x^2 + 5x - 30x - 30
= 12x^2 - 25x - 30
= 4(3x+5)(3x-5) - 5(2x+6)
= (3x+5)(4x-5) - 5(2x+6)