Сократите дробь:
a^2-4/a^2-6a+8

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a²-4 = a² -2² = (a-2)*(a+2)

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a²-6a+8 = 0

D = (-6)² - 4 * 8 = 36 - 32 = 4 = 2²

a²-6a+8 = (a-4)*(a-2)

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