I do not understand how to do this problem please help!

6. Below is a graph that represents the total profits for a third month. Write the equation of the line that represents this graph. Show your work or explain how you determined the equations.

The first month they made 1200 and the second month they made 1500...

graph a line using the slope-intercept form:
Manipulate the equation into slope-intercept form, y = mx + b.
Identify and plot the y-intercept of the line. Remember, the y-intercept is b. Don't forget: The sign goes with the number.
Identify and use the slope of the line to find a second point. Remember, the slope is m. Don't forget: Starting at the y-intercept, the numerator tells you the rise (count up if positive and down if negative), the denominator tells you the run (count right.)
Draw a straight line through the two points to complete the graph.
Linear Functions:
A linear function is a function that is defined by a linear equation.
To write a linear function with function notation, first write it in slope-intercept form, and then replace y with f(x).
The graph of a linear function is all points (x, f(x)), where x is in the domain of the function.