计算:(1) -18+24-(-5); (2) -42×(-)+30÷(-6).
(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)
先化简,再求值:,其中x=6.
(1)计算:; (2)计算:.