Answer:
Job A is more profitable for nearly 49 months (or 50 months including the first month)
Job B is more profitable after 49 months (or 50 months including the first month).
Step-by-step explanation:
Let x be the number of months passed after first month
<u>Job A:</u>
$2,000 for the first month with a $300 raise every month thereafter
Function describing this situation:

<u>Job B:</u>
$1,500 for the first month with a 5% raise every month thereafter
Function describing this situation:

Plot both graphs (see attached diagram). The diagram shows that the job A is more profitable for nearly 49 months (or 50 months including the first month) and the job B is more profitable after 49 months (or 50 months including the first month).
Step-by-step explanation:
<u>Finding Vertex</u>
Given

The vertex of an up-down facing parabola of the form

The Parabola params are:







∵ 





Therefore the parabola vertex is:





<u>Finding symmetry</u>
For a parabola in standard form 
the axis of symmetry is the vertical line that goes through the vertex 




Therefore,
