Question 1:
The generic equation of the line is given by:
Where,
m: slope of the line
b: cutting point with the y axis
Substituting values we have:
Answer: an equation for the line with slope 2/3 and y-intercept is: 
Question 2:
The standard equation of the line is given by:
Where,
m: slope of the line
(xo, yo): ordered pair that belongs to the line
The slope of the line is:
Substituting values:
We choose an ordered pair:
Substituting values:
Rewriting:
Answer: An equation in slope-intercept form for the line that passes through the points (1, -3) and (3,1) is: 
Question 3:
For this case, since the variation is direct, then we have an equation of the form:
Where,
k: constant of variation.
We then have the following equation:
Rewriting we have:
Therefore, the constate of variation is given by:
Answer: the constant of variation is: 
Question 4: For this case, since the variation is direct, then we have an equation of the form:
Where,
k: constant of variation.
We must find the constant k, for this we use the following data:
y = 24 when x = 8
Substituting values:
Clearing k we have:
Therefore, the equation is:
Thus, substituting x = 10 we have that the value of y is given by:
Answer: the value of y when x = 10 is:
