7( а² - 6 ) + ( 7 - 2а )*( 7 + 2a ) = 7a² - 42 + 49 - 4a² = 3a² + 7
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( 4 - 3y )*( 4 + 3y ) + 9y*( y - 6 ) = 16 - 9y² + 9y² - 54y = 16 - 54y
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( 9 - 2x)*( 2x + 9 ) + 0,5x*( 8x - 6 ) = 81 - 4x² + 4x² - 3x = 81 - 3x
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( 1 - 5m)*( 5m + 1 ) + 12,5m*( 2m - 4 ) = 1 - 25m² + 25m² - 50m = 1 - 50m
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0,4*( 10 - 5d) + (11d + 2 )*( 11d - 2 ) = 4 - 2d + 121d² - 4 = 121d² - 2d
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9*(8a - 4 )+ ( 6 - 7a )*( 6 + 7a ) = 72a - 36 + 36 - 49a² = 72a - 49a²