Explain the method used to graph a line using slope and y-intercept?

Question

need help

Answer 1

The Slope-Intercept form of the equation of a line is:  y=mx + b

     where m=slope  (often called "rise over run")

              b = y-intercept   (the point on the y-axis when x=0)

 

Given a slope and a y-intercept point [ (0,b) ],

  (1) plot the point (0,b)

      On the y-axis (x=0), find the point b.

 

  (2) Now, do the "rise over run" exercise.  For a slope of m, you go up m units on the y-axis for 1 unit of increase on the x-axis.  For example, if m=4 the next point after (0,b) would be (1,b+4).  Now, note that a negative m (a negative slope) means that the y-values decrease as the x-values increase.

 

Two points determine a line.  "Connect the dots" and extend in both directions.

Answer 2

The simplest way is to use the point slope formula. The formula is as follows:

 

Y - Y₁ = m(X - X₁)

 

Your points that you use come from the graph or from data given. It will be given in the form:

 

(X₁,Y₁)

 

m in the formula is your slope that you are given. 

 

Now just plug in your numbers for the correct letters and solve the formula for Y. You should get it in the final form:

 

Y = mx + b

 

m is your slope

b is your y-intercept