I need help with this question, I cant get the right answer

a$.)$ Solve the following problems by the two$-$phase simplex method:

$mamize,3x_1+x_2$

subject $to{x}_1-x_2-1$

$,-x_1-x_2-3$

$,2x_1+x_{2}4$

$,x_1,x_{2}0$