Question 1

Find the x & y intercepts for the following linear equation:

                                y = -3x + 9

Extra: Try to draw the line of y = -3x + 9 after finding the x and y intercepts.

Select and check your answer...

A. y-intercept = 3  & x-intercept = -9
B. y-intercept = 3  & x-intercept = 9
C. y-intercept = 9  & x-intercept = 3
D. y-intercept = 9  & x-intercept = -3

Let's find the y-intercept. From the lesson, we know that the y-intercept is the y-coordinate of a point where the line crosses the y-axis.

Therefore, let's imagine the coordinate of that point is (0,y), where:

                    0 = x-coordinate       
                    y = y-coordinate = y-intercept

Now, we can solve for the y-intercept:







From the calculation above, we have the y-intercept as 6.

As for the x-intercept, we know that the x-intercept is the x-coordinate of a point where the line crosses the x-axis.

Therefore, let's imagine the coordinate of that point is (x,0), where:

                    x = x-coordinate = x-intercept      
                    0 = y-coordinate

So, now we can solve for the x-intercept:











From the calculation above, we have the x-intercept as 3.

To summarize, we have:

         y-intercept: 9
         x-intercept: 3

With these intercepts, we have 2 points with the coordinates:

             (0.0,9.0)

             (3.0,0.0)

Hence, by plotting these 2 points on the graph, we are able draw the line of
y= -3x + 9 as shown in the picture.