Hey there,
Can someone explain in detail how the equations on the left side became the ones on the right?
Thanks!
This is “Gaussian Elimination”. I have not taken that course (M4ML), but they must have covered this in the lectures.
You multiply the first equation by the factor you need to eliminate the a term in the second and third equations when you subtract the first equation times the constant from the other two. You’ll need a different constant multiplier in the two cases.
Then you multiply the remaining second equation by the factor that will allow you to eliminate the b term in the last equation when you subtract. Then you solve for c and work your way back up the chain to solve for b and then a.
But the short answer is that if you missed this, you should watch the relevant lecture again or perhaps read the instructions in the assignment if this was part of an assignment.
Or if they don’t cover that in the course materials, you can google “Gaussian Elimination”. Here’s the Wikipedia page you get and here’s a YouTube video lecture that covers it.