Interactive applet

Systems of Linear Equations

Two race cars run parallel lanes at speeds you set. One meeting, no meeting, or always the same mark — the three cases of a linear system.

Both exams

Hands-on lab

0 m3 m6 m9 m12 msame markTeal · 1 mCoral · 7 mt = 0 s
012345678910123456789101112(6, 10)time (s)position (m)

Race · graph · three cases

Two race cars run two parallel lanes. A solution is a time when they are at the same mark — not the same lane. Position is linear in time: d = start + speed · t.

Teal car

d = 1 + 1.5t

Coral car

d = 7 + 0.5t

The system

d = 1 + 1.5t
d = 7 + 0.5t

One solution: t = 6 s, d = 10 m. That ordered pair is where both equations are true.

Missions

  • Watch them meet once (one solution)
  • Same speed, different starts (no solution)
  • Same start and speed (infinitely many)

1/3 complete

Guided questions

Play the race. At what time are the cars at the same mark? What ordered pair is that on the graph?

Reflection

A solution of a system is a pair (t, d) that makes both equations true. Why is that the same as the cars being at the same mark at the same time?

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