Question 785662

if you mean

{{{-12 >=(1/2)z + 1 >=4}}}, then you have

{{{-12-1 >=(1/2)z + 1-1 >=4-1}}}

{{{-13 >=(1/2)z  >=3}}}....all terms multiply by {{{2}}}

{{{-13*2 >=(1/2)*2z  >=3*2}}}

{{{-26 >=(1/cross(2))*cross(2)z  >=6}}}

{{{-26 >= z  >=6}}}