Em tham khảo nha :

\(\begin{array}{l}
a)\\
CTHH:{S_x}{O_y}\\
\% S = \dfrac{{x{M_S}}}{M} \times 100\%  = 40\% \\
 \Rightarrow x = \dfrac{{80 \times 0,4}}{{32}} = 1\\
 \Rightarrow {M_S} + y{M_O} = 80\\
 \Rightarrow y = \dfrac{{80 - 32}}{{16}} = 3\\
 \Rightarrow CTHH:S{O_3}\\
b)\\
CTHH:F{e_x}{S_y}{O_z}\\
\% Fe = \dfrac{{x{M_{Fe}}}}{M} \times 100\%  = 36,8\% \\
 \Rightarrow x = \dfrac{{152 \times 0,368}}{{56}} = 1\\
\% S = \dfrac{{y{M_S}}}{M} \times 100\%  = 21\% \\
 \Rightarrow y = \dfrac{{152 \times 0,21}}{{32}} = 1\\
{M_{Fe}} + {M_S} + z{M_O} = 152\\
 \Rightarrow z = \dfrac{{152 - 56 - 32}}{{16}} = 4\\
 \Rightarrow CTHH:FeS{O_4}
\end{array}\)