Answer:
1) The equation of the line in point slope form is equal to 
2) The equation of the line in slope intercept form is equal to
3) The equation of the line in standard form is equal to 
Step-by-step explanation:
we have that the line passes through the points
(9,11) and (21,27)
step 1
Find the slope
The formula to calculate the slope between two points is equal to
substitute the values
step 2
Find the equation of the line into point slope form
The equation of the line is

we have

substitute
-----> equation of the line into point slope form
step 3
Find the equation of the line in slope intercept form



-----> equation of the line in slope intercept form
step 4
Find the equation of the line in standard form

where
A is a positive integer
B and C are integers

Multiply by 3 both sides to remove the fraction

----> equation of the line in standard form