Răspuns :
4+3x(60+8x(360:a-18)=712
4+3x(60+2880:a-144)=712
4+180+8640:a-432=712
184+8640:a=712+432
184+8640a=1144
8640=1144-184
8640a=960
ax960=8640x1
a=8640:960
a=9
4+3x(60+2880:a-144)=712
4+180+8640:a-432=712
184+8640:a=712+432
184+8640a=1144
8640=1144-184
8640a=960
ax960=8640x1
a=8640:960
a=9