a² - b² = (a - b)(a + b)(a - b)² = a² - 2ab + b²--25(d-1)² - (5d-2)(5d+2) = 25(d² - 2d + 1) - ((5d)² - 2²) = 25d² - 50d + 25 - 25d² + 4 = -50d + 29d = 1/25-50d + 29 = -50*1/25 + 29 = -2 + 29 = 27
a² - b² = (a - b)(a + b)
(a - b)² = a² - 2ab + b²
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25(d-1)² - (5d-2)(5d+2) = 25(d² - 2d + 1) - ((5d)² - 2²) = 25d² - 50d + 25 - 25d² + 4 = -50d + 29
d = 1/25
-50d + 29 = -50*1/25 + 29 = -2 + 29 = 27