(7x-3):6= (5x+1):4 для самоконтроля (-9)
( 7x - 3 ) : 6 = ( 5x + 1 ) : 4 4( 7x - 3 ) = 6( 5x + 1 ) 28x - 12 = 30x + 6 30x - 28x = - 12 - 6 2x = - 18 x = - 18 : 2 x = - 9