Answer: The system of linear inequalities to model the number of hours that you could work at each location in a week are,
Subject : 5x+7y,
and
, where x represents number of hours in tips working at a video store and y represents number of hours working at a landscaping company.
Step-by-step explanation:
Let x represents number of hours in tips working at a video store and y represents number of hours working at a landscaping company.
Therefore total cost which have to be maximized,
Z= 5x+7y,
Now, we must work at least four hours per week at the video store,
Therefore, 
And, the total number of hours you work at both jobs and weak cannot be greater than 15.
Therefore,
Thus, the required system of equation is, Z= 5x+7y,
,
,
Since, at ( 4,11) Z= 97 which is maximum value.
Thus the solution of the above system of equation is x=4 and y=11.