$4\mathrm{.}1-5.$ Repeat Prob. $4\mathrm{.}1-4$ for the following problem.

Maximize $,Z=x_1+2x_2,$

subject to

$x_1+3x_{2}8$

$x_1+x_{2}4$

and

$x_{1}0,x_2$

Solve using the matrix form of the simplex method. Step by step.