$s_1,e_2$ are the slack and excess

variables $of$ constraints $1,2a_2,a_3$ are the artificial variables for constraints $2,3$max,$z=3x1+x2,$

$s.t.2x1+x2,4$

$,3x1+2x2,6$

$,4x1+2x2,=7$

$,x1,x2,0x1,x2$ and the objective $z{y}_1,y_2,y_3$ and the dual objective