Đề kiểm tra – Nâng cao - Bài: Các hằng đẳng thức đáng nhớ

<span class='text_page_counter'>(1)</span>ĐIỂM. ĐỀ KIỂM TRA – NÂNG CAO. LỜI PHÊ. Bài: CÁC HẰNG ĐẲNG THỨC ĐÁNG NHỚ Thời gian: 90 phút. ĐỀ BÀI  x y  ab Bài 1.(2đ) Cho  2 . Chứng minh rằng x 3  y 3  a 3  b 3 2 2 2 x  y  a  b Bài 2.(2.5đ) Rút gọn. . . . . . a/ A  3  1 3 2  1 3 4  1 316  1 332  1. b/ B  a  b  c   a  b  c   b  c  a   c  a  b  2. 2. 2. 2. Bài 3.(1.5đ) Cho a 2  b 2  c 2  m . Tính A theo m biết A  2a  2b  c   2a  2b  c   2a  2c  b  2. 2. 2. Bài 4.(1.5đ) Cho a 2  b 2  4c 2 . Chứng minh rằng 5a  3b  8c 5a  3b  8c   3a  5b . 2. Bài 5 (2.5đ) ... 9900 ... 0025 là bình phương của một số tự nhiên nào đó a/ Chứng minh rằng số 99   n. n. . . b/ Chứng minh rằng nếu (a  b  c)  6 thì a 3  b 3  c 3  6 BÀI LÀM .............................................................................................................................................................................. .............................................................................................................................................................................. .............................................................................................................................................................................. .............................................................................................................................................................................. 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