Grade 9 · Linear systems
Printing machine: Classify line-system outcomes
Printing machine investigation: classify line-system outcomes. Change the quantities, follow the motion, and explain the result using the displayed mathematical relationship.
Predict what will happen, press Play, then pause and explain what changed. Every control also works without playback.
Watch the relationship
PausedHD animation studio
From experiment to screen.
Present a crisp Canvas scene, save a full-HD image, or capture your model as a silent video.
Understand what you are seeing
The idea behind the motion.
A shared solution satisfies two line equations at the same input and output. Different slopes yield one crossing, equal slopes with different intercepts yield none, and identical rules share infinitely many points. Two equations alone do not guarantee a unique solution. This investigation begins with first slope a = 1; second slope b = -1.5; second intercept c = -1. Treat the named setting as a constructed classroom model, then explain which relationships would still hold if its numbers changed.
A relationship to keep
y = ax and y = bx+c; (a−b)x = c
Read the symbols alongside the explanation. A diagram shows the relationship; the assumptions tell you when it applies.
- STEP 1
Represent the given quantities
Read the two rules separately, including the second rule's intercept c.
- STEP 2
Follow the changing model
Playback moves a vertical probe across both graphs so their outputs can be compared at one input.
- STEP 3
Check and explain the relationship
If slopes differ, solve c/(a−b) and substitute into both rules. If slopes match, compare intercepts instead of dividing by zero.
Your turn to explain
Make a prediction. Test your reasoning.
Printing machine: Solve y=1x and y=-1.5x+(-1).
Use the values specified in the question. Reset restores the initial values for this investigation.
Compare your explanation
(-0.4, -0.4). Both rules have output -0.4 at x=-0.4.
Work through a full lesson
Connect the animation to a worked example and practice questions.