倍速课时学练倍速课时学练 回顾与思考 回顾 回顾 ; (5) (5) = = ; ; (4) (4) = = . . ; ; (6) (6) = = . . . . (1) (1) = = ; ; (2) (2) = = ; ; 1 1 2 2 、 、 计算: 计算: (1) (1) a a 20 20 a a 10 10 ; ; (2) (2) a a 2 2n n a a n n (3) (3) ( ( c c ) ) 4 4 ( ( c c ) ) 2 2 ; ; (4) (4) ( ( a a 2 2 ) ) 3 3 ( ( - - a a 3 3 ) ) ( ( a a 3 3 ) ) 5 5 ; ; (5) (5) ( ( x x 4 4 ) ) 6 6 ( ( x x 6 6 ) ) 2 2 ( ( - - x x 4 4 ) ) 2 2 。 。 = = a a 10 10 = = a a n n = = c c 2 2 = = a a 9 9 a a 15 15 = = a a 6 6 = = = = x x 24 24 x x 12 12 x x 8 8 = = x