计算下面各题,能简算的要简算(每题3分,共18分) (1)884÷34+17×21 (2)1.25×3.2×0.25 (3)()÷+ (4)4÷5+39× (5)4.2﹣1.38+5.8﹣4.62 (6)2÷﹣÷2.
已知:如图,在等边三角形ABC的AC边上取中点D,BC的延长线上取一点E,使CE=CD.求证:BD=DE.
如图,在△ABC中,AB=AC,点D、E在BC上,且BD=CE. 求证:△ABE≌△ACD.
计算: (1)3(3x﹣4); (2)(10﹣15)÷5x.
计算:
计算:-2-2+sin45°+|1-|+(3.14-π)0.