Respuesta :

altavistard

Answer:

x^2 + 7x + 12

Step-by-step explanation:

This is a product of two binomials.  There's a formula:  

(a + b)(c + d) = ac + ad + bc + bd.

Therefore, (x + 3)(x + 4)​ = x^2 + 3x + 4x + 12  =  x^2 + 7x + 12