Пусть ( х² + 2x )/ 3 = a
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( 2 - a )( 4 - a ) = 3
8 - 2a - 4a + a² = 3
a² - 6a + 5 = 0
D = 36 - 20 = 16 = 4²
a1 = ( 6 + 4 ) : 2 = 5
a2 = ( 6 - 4 ) : 2 = 1
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( x² + 2x ) / 3 = 5
x² + 2x - 15 = 0
D = 4 + 60 = 64 = 8²
x1 = ( - 2 + 8 ) : 2 = 3
x2 = ( - 2 - 8 ) : 2 = - 5
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( x² + 2x ) / 3 = 1
x² + 2x - 3 = 0
D = 4 + 12 = 16 = 4²
x1 = ( - 2 + 4 ) : 2 = 1
x2 = ( - 2 - 4 ) : 2 = - 3
ОТВЕТ ( - 3 ) ; ( - 5 ) ; 1 ; 3