{[(7*x-5)+2*6]:4+5}*10-[(4+6)*5-42]=112
{[(7x-5)+12]:4+5}*10-(10*5-42)=112
{[(7x-5)+12]:4+5}*10-(50-42)=112
{[(7x-5)+12]:4+5}*10-8=112
{[(7x-5)+12]:4+5}*10=112+8
{[(7x-5)+12]:4+5}*10=120
[(7x-5)+12]:4+5=120:10
[(7x-5)+12]:4+5=12
[(7x-5)+12]:4=12-5
[(7x-5)+12]:4=7
(7x-5)+12=7*4
(7x-5)+12=28
7x-5=28-12
7x-5=16
7x=16+5
7x=21
x=21:7
x=3
