Do any constraints have (nonzero) surplus? If yes which ones and how much surplus does each have? ...

Use simultaneous equations to determine the optimal values of the decisions variables. I am also asked to show GRAPHS and explain my work.
 

Maximize Z=2x1+10x2

Subject to

Durability 10x1+4x2>= 40 wk

Strength 1x1+6x2>=24 psi

Time 1x1+2x2<=14 hr

X1,x2>=0

1. What are the optimal values of the decision variables and Z?

2. Do any constraints have (nonzero) slack? If yes, which ones and how much slack does each have?

3. Do any constraints have (nonzero) surplus? If yes which ones and how much surplus does each have?

4. Are any constraints redundant? If yes, which ones? Explain briefly.