52³ + 25³ (52 + 25) (52² - 52 * 25 + 25²)
--------------- - 52 * 25 = ------------------------------------------- - 52 * 25 =
77 77
77 (52² - 52 * 25 + 25²)
=----------------------------------- - 52 * 25 = 52² - 52 * 25 + 25² - 52 * 25 =
77
= 52² - 2 * 52 * 25 + 25² = (52 - 25)² = 27² = 729
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25b³ - 200 = 25(b-2) (b² + 2b + 4)
16a² - 8ab + b² + 12a - 3b = (4a - b) (4a - b +3)
9x² + у² + 6ху + 18х + 6у + 9 = (3х + у + 3)²
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(4у - 5)² + (2у - 5) (2у + 5) + 65у = 16у² - 40у + 25 + 4у² - 25 + 65у = 20у² + 25у = 20 * (-1)² + 25 * (-1) = 20 + (- 25) = 20 - 25 = - 5