rút gọn a/ (9x-10)² + (1 – 5x) ² + 2(9x – 1)(1 – 5x) b/ (a + b + c) ² + ( a + b – c) ² – 2(a + b)² c/ (2a ² + 2a + 1) ( 2a ² – 2a + 1) – (2a ² + 1) ²
rút gọn a/ (9x-10)² + (1 – 5x) ² + 2(9x – 1)(1 – 5x) b/ (a + b + c) ² + ( a + b – c) ² – 2(a + b)² c/ (2a ² + 2a + 1) ( 2a ² – 2a + 1) – (2a ² + 1) ² d/ … Đọc tiếp