\[\boxed{\mathbf{1117\ (1117)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\(1)\ 0,31x + 1,2 = 1,2124\)
\[0,31x = 1,2124 - 1,2\]
\[x = 0,0124\ :0,31\]
\[x = 0,04\]
\[Ответ:0,04.\]
\(2)\ 0,5x - 17 = 40,52\)
\[0,5x = 40,52 + 17\]
\[x = 57,52\ :0,5\]
\[x = 115,04\]
\[Ответ:115,04.\]
\(3)\ 4,6 - 0,03x = 1,3\)
\[0,03x = 4,6 - 1,3\]
\[x = 3,3\ :0,03\]
\[x = 110\]
\[Ответ:110.\]
\(4)\ 0,4x + 0,24x - 0,26 = 0,764\)
\[0,64x = 0,764 + 0,26\]
\[0,64x = 1,024\]
\[x = 1,024\ :0,64\]
\[x = 1,6\]
\[Ответ:1,6.\]