Respuesta :

9514 1404 393

Answer:

  x² +15x +56

Step-by-step explanation:

We presume these are dimensions of a rectangle, so the area is their product.

  A = (x +8)(x +7) = x(x +7) +8(x +7) = x² +7x +8x +56

  A = x² +15x +56