Cho m gam bột sắt vào dung dịch X chứa AgNO3 và Cu(NO3)2

Tính theo pt: \(\begin{matrix} \underbrace{X:Fe:(x+y)}\\ m \ gam \end{matrix} \ + \left\{\begin{matrix} 2AgNO_{3}:2x \\ Cu(NO_{3})_{2}:t \end{matrix}\right.\rightarrow \left\{\begin{matrix} Fe^{2+}:x+y \ \ \ \\ Cu^{2+} \ du: t-y \\ NO_{3}^- : 2x + 2t \end{matrix}\right.\rightarrow \left\{\begin{matrix} \xrightarrow[]{\ Theo \ a \ } 90(x+y)+98(t-y)=a \\ \xrightarrow[]{\ Theo \ b \ }80(x+y)+80(t-y)=b \\ \xrightarrow[]{\ Theo \ c \ }56(x+y)=m \ \ \ \ \ \ \ \ \ \ \ \ \ \end{matrix}\right.\)
\(\left\{\begin{matrix} x+y=\dfrac{m}{56} \ \ \ \ \ \ \ \\ t-y=\dfrac{b}{80} - \dfrac{m}{56} \end{matrix}\right.\rightarrow 90.\dfrac{m}{56}+98.(\dfrac{b}{80}-\frac{m}{56})=a\rightarrow m=8,575b - 7a\)