计算:
解方程: 3 x 2 - 3 x - 1 x - 3 = 1 .
计算: 18 + ( 2 - 1 ) 2 - 9 1 2 + ( 1 2 ) - 1 .
解方程: 1 x - 2 - 4 x 2 - 4 = 1 .
计算: | 3 - 1 | - 4 1 2 - 12 + ( 1 3 ) - 2 .
化简: ( a - 2 a + 2 + 8 a a 2 - 4 ) ÷ a + 2 a 2 - 2 a