Question 673687

{{{a -12 = -3}}}....add {{{12}}} to both sides

{{{a -12+12 = 12-3}}}


{{{a -cross(12)+cross(12) = 9}}}


{{{highlight(a= 9)}}}



{{{97 = -23 + y}}}......add {{{23}}} to both sides

{{{97+23 = 23-23 + y}}}

{{{97+23 = cross(23)-cross(23) + y}}}

{{{highlight(120 = y)}}}