How do you graph the lines using slope-intercept form h(x) = -x+7h(x)=x+7?

1 Answer
Feb 1, 2016

graph{-x+7 [-10, 10, -5, 5]}

Explanation:

1) Use the equation and what we know about slope-intercept form to find the slope and y-intercept.

h(x)=-x+7h(x)=x+7

The slope-intercept form equation is: y=mx+by=mx+b

Therefore, the slope (mm) is -11 and the y-intercept (bb) is 77.

2) Find the *x-intercept*

Set the equation equal to 00 to find the x-intercept

0=-x+70=x+7
0-7=-x cancel(+7)-7
-7=-x
x=7

So the x-intercept is (7,0)

3) Use what we know to create a graph

  • Because of the y-intercept , we know the graph crosses the y-axis at (0,7).
  • Because of the x-intercept, we know that the graph crosses the x-axis at (7,0)
  • Because the slope is negative, we know that the graph is going down.
  • Because the slope is rise over run we can use up 1 over 1 to graph a few points and create a line

OR

Create a table or list of coordinates by:

  • x-1, y+1 if using the x-intercept. So: (7,0), (6,1), (5,2),etc.

or

  • x+1, y-1 if using the y-intercept. So: (0,7), (1,6), (2,5), etc.