Respuesta :
[tex](x + 4)(x + 2) = {x}^{2} + 6x + 8[/tex]
[tex](x + 3)(x - 5) = {x}^{2} - 2x -15 [/tex]
[tex](x - 4)(x + 1) = {x}^{2} - 3x - 4[/tex]
[tex](a + 5)(a + 4) = {a}^{2} + 9a + 20[/tex]
Explicación paso a paso:
(x+4) (x+2) = x^2+2x+4x+6 = x^2+6x+6
(x+3) (x-5) = x^2-5x+3x-8 = x^2-2x-8
(x+4) (x+1) = x^2+x+4x+4 = x^2+5x+4
(a+5) (a+4) = a^2+4a+5a+9 = a^2+9a+9