Question

Who can help me please to understand only one step by inverse matrix (is on picture)

Answer 1

which step

Answer 2

I do a red circle of the step when I add row 1 and row 3

Answer 3

then in the third row in the midle must be 1 and not zero

Answer 4

row 2 I mean dont row 1

Answer 5

also I write only row 2 and row 3

Answer 6

They are adding row 3 to row 2 not row 2 to row 3. Does that help?

Answer 7

\[\begin{array}{rrr|rrr} {\color{red}1}& -0,5 & 0 & 0,5 & 0 & 0\\ {\color{red}0}&{\color{red}1}& -0,8 & -0,2 & 0,4 & 0\\ {\color{red}0}&{\color{red}0}&{\color{red}1}& -1 & 2 & 5 \end{array}\]

Answer 8

ok but when I add 0 and 1 became 1

Answer 9

Here this might make it better to write out all the steps they did: \[\left[\begin{matrix} ... & ... & ... \\ 0 & 1 & -4/5 \\ 0 & 0 & 1\end{matrix}\right]\] Now multiply the bottom row by 4/5 to get: \[\left[\begin{matrix} ... & ... & ... \\ 0 & 1 & -4/5 \\ 0 & 0 & 4/5\end{matrix}\right]\] add the bottom row to the second row \[\left[\begin{matrix} ... & ... & ... \\ 0 & 1 & 0 \\ 0 & 0 & 4/5\end{matrix}\right]\] divide the bottom row by 4/5 again (same as multiplying by 5/4) \[\left[\begin{matrix} ... & ... & ... \\ 0 & 1 & 0 \\ 0 & 0 & 1\end{matrix}\right]\]

Answer 10

R3*0,8+R3 now in the middle we have a 1 and 0 when I add them became 1

Answer 11

R2

Answer 12

R3*0,8+R2

Answer 13

No, you need to add row 3 to row 2 NOT row 2 to row 3.

Answer 14

Look at the side bar and be careful! These are not the same thing! \[\LARGE II + \frac{4}{5} III \ne III +\frac{4}{5} II\]

Answer 15

a ok but I cant do the inverse row 2 add row3*4/5?