Given:
Lan is working two jobs:
1) $19 per hour life guarding
2) $9 per hour clearing tables
The total hours per week = 14
He must earn a minimum of $180
Let x represents the number of hours life guarding and y represents the number of hours clearing tables
So, we have the following inequalities

We need to solve the inequalities by graph
So, we will graph the lines: x + y = 14 and 19x + 9y = 180
The shaded area represents the solution of the system of inequalities
The following figure represents the solution of the system of inequalities