The Zero Trap: Points on Axes
Find the secret coordinate for points that sit exactly on the x or y axis.
Equation
y = x
Graph
Table
| x | y |
|---|---|
| -4 | -4 |
| -3 | -3 |
| -2 | -2 |
| -1 | -1 |
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
What this lesson covers
What you do
You shape the function y = m*x + c and watch the graph answer.
Challenges to clear
- Place the line so it passes through (-4, 0). This point is on the x-axis — its y is the secret 0.
- And through (0, 4): on the y-axis the SECRET coordinate is x = 0.
- New pair of axis points. Send the line through (0, −3): sitting on the y-axis, its secret coordinate is x = 0.
- Now tilt it through (6, 0) as well — on the x-axis the hidden coordinate is y = 0.
Check yourself
A point lies exactly on the y-axis. Which coordinate MUST be zero?
If a point is on the x-axis, its coordinate pair looks like...
- The x-coordinate, because it has no horizontal distance from the vertical axis. — correct
- The y-coordinate, because it is sitting on the horizontal axis.
- Both coordinates, because axes only exist at the origin.
- Neither, because axes are lines and points have no size.
- (0, a)
- (a, 0) — correct
- (a, a)
- (0, 0)
Think about it
- Look at the table. When the line crosses the x-axis, what is the value of y?