1)\(\left(x-280\right):35=56.5\)
\(\left(x-280\right):35=280\)
\(x-280=280.35\)
\(x-280=9800\)
\(x=9800+280\)
\(x=10080\)
2) \(\left(x-128+20\right):192=0\)
\(\Rightarrow\left(x-148\right):192=0\)
\(\Rightarrow x-148=0\)
\(\Rightarrow x=0+148\)
\(\Rightarrow x=148\)
3) \(460+85.4=\left(x+200\right).4\)
\(\Rightarrow\left(x+200\right).4=460+340\)
\(\Rightarrow\left(x+200\right).4=800\)
\(\Rightarrow x+200=800:4=200\)
\(\Rightarrow x+200=200\)
\(\Rightarrow x=200-200=0\)
4) \(x+5.2-\left(32+16.3:16-15\right)=0\)
\(\Rightarrow x+10-\left(32+3-15\right)=0\)
\(\Rightarrow x+10-20=0\)
\(\Rightarrow x+10=20\)
\(\Rightarrow x=20-10=10\)
nha m.n