You are given two points that lie on a line. Explain how you would find an equation of the line.

Question

Choose the correct answer below.

A.
First use the given points to find the slope of the line. Then find the average of the x-coordinates and the average of the y-coordinates. Substitute the slope and the averages into the standard form of the equation of a line. Write the equation in point-slope form or in slope-intercept form.

B.
First substitute the coordinates of one of the points into the slope-intercept form of the equation of a line. Then solve this equation for the y-intercept. Next substitute the y-intercept and the coordinates of the other point into the slope-intercept form of the equation of a line. Write the equation in standard form or in point-slope form.

C.
First use the given points to find the slope of the line. Then substitute the slope and the coordinates of both points into the point-slope form of the equation of a line and solve for the y-intercept. Substitute the slope and the y-intercept into the slope-intercept form of the equation of a line.

D.
First use the given points to find the slope of the line. Then substitute the slope and the coordinates of one of the points into the point-slope form of the equation of a line. Write the equation in standard form or in slope-intercept form.

Answer 1

D is straightforward, lucid, eminently correct, and is therefore my choice of correct answer.