Respuesta :

maselalewatle

Answer:

[tex]3x { }^{2} + 16x + 21[/tex]

Step-by-step explanation:

[tex]3x \times x = 3x {?}^{2} [/tex]

[tex](3x \times 3 = 9x) + (7 \times x = 7x)[/tex]

[tex]7 \times 3 = 21[/tex]

FOIL method.