Write the slope intercept form equation from the graph.

For this case we have that by definition, the equation of a line in the slope-intersection form is given by:

Where:

m: It's the slope

b: It is the cut-off point with the y axis

According to the image, the line goes through the following points:

So, the slope is:

Thus, the equation is of the form:

We substitute a point and find "b":

Finally, the equation is:

problem:

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

f(5/2) = 10/3

i hope this !