Phân tích đa thức thành nhân tử: (5x – 2y)(5x + 2y) + 4y – 1.
Giải thích
(5x – 2y)(5x + 2y) + 4y – 1
= 25x2 – 4y2 + 4y – 1
= 25x2 – (4y2 – 4y + 1)
= 25x2 – (2y – 1)2
= (5x + 2y – 1)(5x – 2y + 1)
(5x – 2y)(5x + 2y) + 4y – 1
= 25x2 – 4y2 + 4y – 1
= 25x2 – (4y2 – 4y + 1)
= 25x2 – (2y – 1)2
= (5x + 2y – 1)(5x – 2y + 1)