The line r passes through the points (a, 0) and (0, 2a) where a>1. What is the slope of line r?

Question

I dont know how to solve 

Answer 1

In the Standard Formula for the equation of a line,  y = mx + b

       m is the slope  and  b is the y-intercept

 

The slope is often called "rise over run" because it measures the increase in y-values divided by the increase in x-values.

  The formula for slope  (given two points) is:

     (y₂ - y₁) / (x₂ - x₁)

 

For this problem, we have two points.  The slope is:

    (2a - 0) / (0 - a)

        2a/(-a)

           -2

 

Note:  a>1 limits the values for a, but it does not change the slope of the line.  A value of a=0 makes the division impossible -- but slope m=0 is a horizontal line.

Answer 2

y = mx + b

 

from point (a,0) we have x1 = a, y1 = 0

 

        point (0, 2a), we have x2 = 0, y2= 2a

 

Find the slope, we have equation: m = (y2-y1)/ (x2 - x1) = (2a - 0)/ (0-a) = 2a/ -a = -2

 

Slope is -2