Răspuns:
7+{48:(18-b)+49}=26×3
7+{48:(18-b)+49}=78
7+48:18-b=78-49
7+48:18-b=29
48:18-b=29-7
48:18-b=22
18-b=22×48
18-b=1056
b=1056-18
b=1038