№ 1.
а) ( 3 + a ) * ( 2a +1 ) = 6a +2a² + 3 +a = 7a + 2a² + 3.
б) ( 5a + a²) * ( 3 - 2a) = 15a + 3a² - 10a² - 2a³ = 15a - 7a² - 2a³.
в) ( 3 - x ) * ( 2 - 4x ) = 6 - 2x - 12x + 4x² = 6 - 14x + 4x².
г) ( - x -3) * ( 2x - 4) = -2x² - 6x + 4x + 12 = -2x² - 2x +12.
№ 2.
а) 8 - ( 2 + a ) * ( 3a + 4) = 8 - ( 6a + 3a² + 8 + 4a ) = 8 - 6a - 3a² - 8 + 4a = -6a - 3a² + 4a = 4a - 6a -3a².
б) 2a² + ( a + a² ) * ( 5 - 2a ) = 2a² + ( 5a + 5a² - 2a² - 2a³) = 2a² + 5a + 5a² - 2a² - 2a³ = 5a + 5a² - 2a³.
в) ( 1 - x ) * ( 2 + 2x) + ( 2 - x ) * ( 1 - 2x ) = ( 2 - 2x + 2x - 2x² ) + ( 2 - x - 2x + 2x² ) = 2 + 2x - 2x - 2x² + 2 - x - 2x + 2x² = 4 - 3x.
г) ( x - 2 ) * ( x - 5 ) - ( x - 3 ) * ( x - 4 ) = ( x² - 2x - 5x + 10 ) - ( x² - 3x - 4x +12 ) = x² - 7x + 10 - x² + 7 x - 12 = -2.
№ 3.
а) 3x² - 6x = 3x * ( x - 1 ).
б) x * ( x - 3 ) - 8 * ( x - 3 ) = ( x - 8 ) * ( x - 3).