计算: | - 2 | + 9 × ∣ 1 2 - 1 - 4 × 1 2 - ( π - 1 ) 0 .
计算:(每小题3分,共6分) (1)(2)
先化简:,再选取一个合适的a值代入计算.
(1)计算:-(-1)2+(-2012)0 (2))因式分解:m3n-9mn.
(1)解方程:x2﹣4x+2=0 (2)解不等式组:.
计算: (1)计算: (2)计算:3(x2+2)﹣3(x+1)(x﹣1)