计算:
(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
先化简,再求值 ( 1 a - b - b a 2 - b 2 ) ÷ a 2 - ab a 2 - 2 ab + b 2 ,其中 a , b 满足 a + b - 1 2 = 0 .
计算 - ( - 2 ) + ( π - 3 . 14 ) 0 + 27 3 + ( - 1 3 ) - 1