\(x-157=458\)
\(x=458+157\)
\(x=615\)
\(b\)) \(735-\left(457+x\right)=124\)
\(457+x=735-124\)
\(457+x=611\)
\(x=611-457\)
\(x=154\)
\(c\)) \(2.x+3=15\)
\(2.x=15-3\)
\(2.x=12\)
\(x=12\div2\)
\(x=6\)
\(d\)) \(\left(x-1954\right).5=50\)
\(x-1954=50\div5\)
\(x-1954=10\)
\(x=1954+10\)
\(x=1964\)
\(e\)) \(30.\left(60-x\right)=30\)
\(60-x=30\div30\)
\(60-x=1\)
\(x=60-1\)
\(x=59\)