计算:(1) (2)(3)-49=0 (4)(5)=-8 (6)1-
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)