Respuesta :

[tex]\\ \sf\longmapsto 3x+(x+7)(2x-1)[/tex]

[tex]\\ \sf\longmapsto 3x+(x(2x-1)+7(2x-1))[/tex]

[tex]\\ \sf\longmapsto 3x+2x^2-x+14x-7[/tex]

[tex]\\ \sf\longmapsto 2x^2+3x+13x-7[/tex]

[tex]\\ \sf\longmapsto 2x^2+16x-7[/tex]

Step-by-step explanation:

3x + (x + 7)(2x - 1) =

3x + (2x²-x+14x-7) =

3x + 2x²+13x-7 =

2x²+16x-7