Legal moves when row reducing a matrix involve swapping, summing, and scaling.
swapping, summing, and scaling
1. To swap two rows, touch an entry in
one of the rows and drag it to the row you want to swap with.
2. To add two rows together, press the "+" button next
to one of the rows, then drag to the row where you want their
sum to end up.
3. To scale a row, click on the
"scalar" button (top left) and enter a real number for your scalar.
Then tap or swipe the left dot next to the row you want
to scale.
4. (Advanced) To add a scaled row to another row, choose
your scalar, and drag one row's left dot across the row to the "+"
button. Then drag up/down to the row where you want the result
to end up, and release.
Use your math skills to get a matrix in reduced row echelon form (RREF)
in as few moves as possible:
1
0
0
0
w
0
1
0
0
x
0
0
1
0
y
0
0
0
1
z
(where w, x, etc. are real numbers)
Basically, the last column can be anything,
there is a staircase of 1's from the top left corner,
and everything above/below those 1's is 0. (Learn more)