Răspuns :
( 5x - 1 ) × 20 = 380
5x = ( 380 : 20 ) + 1
5x = 19 + 1
5x = 20
x = 20 : 5
x = 4
(5x - 1)·20 = 380 <=> 5x - 1 = 380 : 20 <=> 5x - 1 = 19 <=> 5x = 19 + 1 <=> 5·x = 20 <=> x = 20 : 5 <=> x = 4
( 5x - 1 ) × 20 = 380
5x = ( 380 : 20 ) + 1
5x = 19 + 1
5x = 20
x = 20 : 5
x = 4
(5x - 1)·20 = 380 <=> 5x - 1 = 380 : 20 <=> 5x - 1 = 19 <=> 5x = 19 + 1 <=> 5·x = 20 <=> x = 20 : 5 <=> x = 4