I want to solve the following simplex algorithm :
Maximize $$z =x_1+x_2+2x_3-2x_4$$ Subject to $$ x_1+2x_3 \le 700 $$ $$ 2x_2-8x_3 \le 0 $$ $$ x_2-2x_3+2x_4 \ge 1 $$ $$ x_1+x_2+x_3+x_4 = 10 $$ where $$ 0 \le x_1 \le 10$$ $$ 0 \le x_2 \le 10$$ $$ 0 \le x_3 \le 10$$ $$ 0 \le x_4 \le 10$$
I know that the standard simplex problem has following form :
Maximize $$z=c_1x_1+c_2x_2+ \ldots + c_n+x_n$$ Subject to $$a_{11}x_1+a_{12}x_2+a_{13}x_3+\ldots+a_{1n}x_n \le b1$$ $$a_{11}x_1+a_{12}x_2+a_{13}x_3+\ldots+a_{1n}x_n \le b2$$ Subject to $$\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots $$ $$a_{m1}x_1+a_{m2}x_2+a_{m3}x_3+\ldots+a_{mn}x_n \le bm$$
where $$ x_j \ge 0 , j=1,2,3,\ldots,n$$
How can I convert my problem to standard form ? How can I solve my problems by simplex algorithm ?
My attempt:
I have replaced $0 \le x_1 \le 10 $ by two separate constraints $ 0 \le x_1 $ and $ x_1 \le 10 $. But after that, I can't reach to optimal solution although the problem has basic feasible solution.