... S =973 + 83 3 180 - 97 . 83 =(93 + 87 )(972 – 97 . 83 + 83 2 ) 180 - 97. 83 = 180 (972 – 97 . 83 + 83 2 ) 180 - 97. 83 = 972 - 97 . 83 + 83 2 – 97 . 83 = (97 – 83 )2 = 142 ... 47) = 100 . 6 = 600 c. 31, 8 2 – 2 . 31, 8 . 21, 8 + 21, 8 2 = (31, 8 – 21, 8) 2 = 102 = 100 d, 58, 22 + 2 . 58, 2 . 41, 8 + 41, 8 2 = ( 58, 2 + 41, 8) 2 = 1002 = 10000 NhËn ... -25x6 – y 8 + 10x3y4 d, 1/ 4x2 – 5xy + 25y2 Bµi tËp 3: TÝnh nhanha. 752 – 252 c, 31, 8 2 – 2 . 31, 8 . 21, 8 + 21, 8 2b. 532 – 472 d, 58, 22 + 2 . 58, 2 . 41, 8 + 41, 8 2Bµi...