Respuesta :

1/2 *(a+b)-(a-b)²
a=18, b=14
1/2 *(18+14)-(18-14)²=1/2 *(18+14)-(18-14)²= 1/2*32-4²=16-16=0
answer D

answer B 
2 factors have 2 terms: (x+4) and (y+4)