y = mx + c

In this activity, you will use applets to explore the effects of gradient and y-intercept on straight lines.

Question 1

What happens when m (the gradient) is positive?

As x increases, y decreases As x increases, y increases

Question 2

What happens when m (the gradient) is negative?

As x increases, y increases As x increases, y decreases

Question 3

What happens when c (the y-intercept) is positive?

The line always passes through the positive y-axis The line always passes through the negative y-axis The line always goes through the point (0,0)

Question 4

What happens when c (the y-intercept) is negative?

The line always goes through the point (0,0) The line always passes through the negative y-axis The line always passes through the positive y-axis As x increases, y increases As x increases, y decreases

Question 5

What happens when c (the y-intercept) is zero?

The line always goes through the point (0,0) The line always passes through the positive y-axis The line always passes through the negative y-axis

Question 6

Describe the lines where m (the gradient) is zero?

[size=150]Simultaneous Equations[/size]

Question 7

On the graph above, show the graph of y = x + 2. [br][br][i][b]On the same graph[/b][/i], plot the graph of y = 2x - 2[br][br]What do you notice about these lines? Are there any special points for these lines? What are the coordinates of these points?