Răspuns:
Explicație pas cu pas:
a) ( 4 x + 6 y) ( 4 x - 6 y ) =(4 x)² - ( 6 y)² = 16 x² - 36 y²
b) ( 10 x + 7)² = (10x)² + 2 × 10 x × 7 + 7²= 100 x² + 140 x + 49
c) ( 13 x - 4 y )² = (13x)² - 2 × 13 x ×4 y + 4² y² = 169 x² - 104xy +16 y²
d) ( 5 b - 6 c)² = 5²b² - 2 ×5b×6c + 6²c² = 25 b² - 60 bc + 36 c²
