Răspuns :
[ ( y + 540 : 6 ) × 7 - 100 ] : 4 : 5 = 30
[ ( y + 90 ) × 7 - 100 ] : 4 : 5 = 30
[ ( y + 90 ) × 7 - 100 ] : 4 = 30 × 5
[ ( y + 90 ) × 7 - 100 ] : 4 = 150
[ ( y + 90 ) × 7 - 100 ] = 150 × 4
[ ( y + 90 ) × 7 - 100 ] = 600
[ ( y + 90 ) × 7 ] = 600 + 100
[ ( y + 90 ) × 7 ] = 700
y + 90 = 700 : 7
y + 90 = 100
y = 100 - 90
y = 10
[ ( y + 90 ) × 7 - 100 ] : 4 : 5 = 30
[ ( y + 90 ) × 7 - 100 ] : 4 = 30 × 5
[ ( y + 90 ) × 7 - 100 ] : 4 = 150
[ ( y + 90 ) × 7 - 100 ] = 150 × 4
[ ( y + 90 ) × 7 - 100 ] = 600
[ ( y + 90 ) × 7 ] = 600 + 100
[ ( y + 90 ) × 7 ] = 700
y + 90 = 700 : 7
y + 90 = 100
y = 100 - 90
y = 10
Răspuns
[(y+90)*7-100]:4=30*5
[(y+90)*7-100]:4=150
(y+90)*7-100=150*4
(y+90)*7-100=600
(y+90)*7=600+100
(y+90)*7=700
y+90*7=700
y+90=700:7
y+90=100
y=100-90
y=10