Week 1 | Lesson 5 | Interpreting matrices (for solutions)

At 18:13 I misspeak and say "five 3D shapes" when we actually have three 5D shapes. I said it correctly earlier in the video but wanted to clarify my mistake at 18:13.
0:00 Recap of matrices so far
0:56 What do the three given matrices represent?
1:29 Solutions from Matrix 1
3:02 Solutions from Matrix 2
4:14 Solutions from Matrix 3
6:06 How do we write the solutions for Matrix 3?
6:38 Free variable (definition)
9:11 Parametric description of a solution set
11:52 Relating pivots and dimension to the number of solutions
14:08 Worked example