Question

3+3x{3+3x[3+3x(3-3:a)]}=3x31

Answer 1

3+3[3+3(3+9-9:3a)]=93
3+3(3+9+27-27:9a)=93
3+3(39-27:9a)=93
3+117-81:27a=93
120-81:27a=93 / :3
40-27:9a=31
40-3a=31
-3a=31/40
a= - 31/40/3
a= - 31/40 *1/3
a= - 31/120