a) y² - 16 , б) 25с²-1, в) (а+3)²
а) (y-4)^2 = y^2 - 2×y×4 + 4^2 = y^2 - 8y + 16
б) (5c+1)(5c-1) = (5c)^2 - 1^2
в) a^2 + 6a +9= a^2 + 2×a×3 + 3^2 = (a+3)^2
a) y² - 16 , б) 25с²-1, в) (а+3)²
а) (y-4)^2 = y^2 - 2×y×4 + 4^2 = y^2 - 8y + 16
б) (5c+1)(5c-1) = (5c)^2 - 1^2
в) a^2 + 6a +9= a^2 + 2×a×3 + 3^2 = (a+3)^2