[ ( 3 x - 2 ) × 5 - 1 ] : 2 + 5 = 7
[ ( 3 x - 2 ) × 5 - 1 ] : 2 = 7 - 5
[ ( 3 x - 2 ) × 5 - 1 ] : 2 = 2
( 3 x - 2 ) × 5 - 1 = 2 × 2
( 3 x - 2 ) × 5 - 1 = 4
( 3 x - 2 ) × 5 = 4 + 1
( 3 x - 2 ) × 5 = 5
3 x - 2 = 5 : 5
3 x - 2 = 1
3 x = 1 + 2
3 x = 3
x = 3 : 3
x = 1
