Solve the Standard Minimization Problem Using Duality $$c = 7 s + 6 t$$

Short Answer

Solve the standard minimization problem using duality.
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Minimize $$c = 7 s + 6 t$$ ​
subject to $$\begin{array} { l } s + t \geq 12 \\7 s + t \geq 42 \\s \geq 0 , t \geq 0\end{array}$$ ​ $$c =$$ __________
​ $s =$ __________
​ $t =$ __________