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I. a + b = b + a ( ) III. a + 0 = a.
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IV. a + ( a) = 0.
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I. 1 a = a, 0 a = 0, m 0 = 0, (1) a = a. II. m a = a m, | m a | = | m | | a |.
III. m (n a) = (m n) a. ( ).
IV. (m + n) a = m a + n a, (
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L1 L2 ,.. tg k1 k2 + 1 = 0.
L1 L2 :
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