A: Na+、Mg2+、NO3-、Cl-
B:Al3+、K+、OH-、NO3-
C: Na+、Ba2+、Cl-、SO42-
D: H+、K+、SO42―、Fe3+
Where is my ? I can't find it.
解方程或解比例。
①6x-18=36
②x- 34 x=2
③ 1.20.5 = 3x