1) PTK \(Fe_2\left(SO_4\right)_x=400\) đvC
\(\Rightarrow2.56+96.x=400\)
\(\Rightarrow x=3\)
2) PTK \(Fe_xO_3=160\) dvC
\(\Rightarrow56x+16.3=160\)
\(\Rightarrow x=2\)
3) PTK \(Al_2\left(SO_4\right)_x=342\) đvC
\(\Rightarrow27.2+96.x=342\)
\(\Rightarrow x=3\)
4) PTK \(K_2\left(SO_4\right)_x=174\) đvC
\(\Rightarrow2.39+96.x=174\)
\(\Rightarrow x=1\)