(x + 4) (x + 15) = (2x - 5) (2x + 3) =

[tex](x + 4)(x + 15) = {x}^{2} + 15x + 4x + 60 = {x}^{2} + 19x + 60[/tex]
[tex](2x - 5)(2x + 3) = 4 {x}^{2} + 6x - 10x - 15 = 4 {x}^{2} - 4x - 15[/tex]
maaf kalau salah