\(a,\Rightarrow1485,925-x-225=755\)
\(\Rightarrow1485,925-x=755+225\)
\(\Rightarrow1485,925-x=980\)
\(\Rightarrow x=1485,925-980\)
\(\Rightarrow x=505,925\)
\(b,\Rightarrow\left(9-5,34\right):x=3\)
\(\Rightarrow3,66:x=3\)
\(\Rightarrow x=3,66:3\)
\(\Rightarrow x=1,22\)