计算: - | 4 - 12 | - ( π - 3 . 14 ) 0 + 1 - cos 30 ∘ × 1 2 - 2 .
计算:
(1) x ( x - 2 y ) - ( x + y ) 2
(2) ( 3 a + 2 + a - 2 ) ÷ a 2 - 2 a + 1 a + 2 .
计算:(1) ( x - y ) 2 - ( x - 2 y ) ( x + y ) (2) x 2 + 4 x + 4 x 2 + 2 x ÷ ( 2 x - 4 + x 2 x )
(1) ( a + b ) 2 - b ( 2 a + b )
(2) ( 2 - 2 x x + 1 + x - 1 ) ÷ x 2 - x x + 1 .
计算: 3 2 + ( π - 5 ) 0 - 4 + ( - 1 ) - 1 .
计算: 18 - 2 cos 45 ° + ( 1 3 ) - 1 - ( π - 1 ) 0