Răspuns :
(a-15)×2-[9×2-24÷4+(100-9×5)×0]=12
(a-15)x2-[18-6+(100-45)x0]=12
(a-15)x2-(12+55x0)=12
(a-15)x2-12=12
(a-15)x2=12+12
(a-15)x2=24
a-15=24:2
a-15=12
a=15+12
a=27
(a-15)×2-[9×2-24÷4+(100-9×5)×0]=12
(a-15)x2-[18-6+(100-45)x0]=12
(a-15)x2-(12+55x0)=12
(a-15)x2-12=12
(a-15)x2=12+12
(a-15)x2=24
a-15=24:2
a-15=12
a=15+12
a=27