The question goes...

Use the simplex method to solve the following linear programming problem. Maximise

$\displaystyle f(x_1, x_2, x_3)=3x_1+2x_2+4x_3$

subject to the constraints

$\displaystyle 3x_1+x_2+4x_3\leq60$

$\displaystyle x_1+2x_2+3x_3\leq30$

$\displaystyle 2x_1+2x_2+3x_3\leq600$

$\displaystyle x_1, x_2, x_3\geq0$