Answer :
[tex]180-x=10+2(90-x)\ \ \ \ \ |Omit\ the\ bracket\\\\
180-x=10+180-2x\ \ \ |Add\ 2x\\\\
180+x=190\ \ \ |Subtract\ 180\\\\
x=10\\\\Solution\ is\ x=10.[/tex]
180 - x = 10 + 2(90-x)
180 - x = 10 + 180 - 2x
180 - x = 190 - 2x
180 = 190 -1x
-10 = -1x
10 = x
180 - x = 10 + 180 - 2x
180 - x = 190 - 2x
180 = 190 -1x
-10 = -1x
10 = x