(1)计算: ( - 2 ) 2 + tan 45 ° - ( 3 - 2 ) 0
(2)化简: x ( x + 1 ) - ( x + 1 ) ( x - 2 )
计算:
计算:(1); (2).
先化简下式,再求值:(-x2+3-7x)+(5x-7+2x2),其中.
计算:.