Solve given linear programming model by simplex method:
Maximize Z = $70x1 + $80x2
Subject to: -2x1 + x2 >= -20
x1 + x2 <= 14
x1 + 2x2 <= 20
x1 , x2 >= 0
Show each table and equations to make new row for each table. use fractions only (if applicable), no decimals.