解下列方程或比例(每题3分,共12分) (1):=:x (2)= (3)2x﹣=0.5 (4)x+x=
计算①–2-5+23-9+7 ② ③ ④
(本题6分)计算:
计算: (1) (2)
计算:(每题4分,共8分)(1)(2)
(8分)计算:(1)(2)(3); (4)