Răspuns:
x=7
Explicație pas cu pas:
385-[180-2(50-35:x):9]=5×3+13×15+40:8
385-[180-2×(50x-35)/x×1/9]=215
385-[180-(100x-70)/9x]=215
385-180+(100x-70)/9x=215
(100x-70)/9x=215-205
100x-70=90x
100x-90x=70
10x=70
x=70:10
