Just a few suggestions/corrections for the Ungraded Lab about solving linear equations.

**Introduction**

```
* Use `NumPy` linear algebra package to find the solutions to the system of linear equations
* Perform row reduction to bring matrix into row echelon form
* Find the solution for the system of linear equations using row reduced matrix
* Evaluate the determinant of the matrix to see again the connection between matrix singularity and the number of solutions of the linear system
```

I think the following sounds more like natural English (just a few minor wording tweaks):

```
* Use the `NumPy` linear algebra package to find the solutions to a system of linear equations
* Perform row reduction to bring a matrix into row echelon form
* Find the solution for a system of linear equations by using a row reduced matrix
* Evaluate the determinant of a matrix to see the connection between matrix singularity and the number of solutions of the linear system
```

**Section 1.2**

`each column will correspond to the variable π₯1, π₯2, π₯3.`

I think it sounds better to say:

`each column will correspond to the variables π₯1, π₯2, π₯3.`

**Section 1.3**

`Let's calculate the determinant using `

np.linalg.det(A)` function:`

This construct appears in a number of places and I donβt have the energy to document all of them, but the more natural way to write that would be:

`Let's calculate the determinant using the `

np.linalg.det(A)` function:`

But I guess maybe since the audience includes a lot of students who are not native English speakers, maybe it makes them feel more comfortable when they see the signs that the author is also not a native English speaker. So I submit all this for your judgement: do what feels right to you and feel free to ignore my nit-picking.

`Please, note that its value is non-zero, as expected.`

I think it would look more normal to omit the first comma there:

`Please note that its value is non-zero, as expected.`

**Section 2.3**

`the arithmetics of operations is easier then`

I think the following would sound better:

`the arithmetic of the operations is easier then`

Or maybe even:

`the arithmetic of the operations will be easier then`