计算:
(1) a ( a + 2 b ) - ( a + b ) ( a - b )
(2) ( x + 2 x - 3 + x + 2 ) ÷ x 2 - 4 x + 4 x - 3
解方程: ⑴(用配方法)⑵
.2+-4
化简.(a>0)
化简.