- #1

karush

Gold Member

MHB

- 3,269

- 5

Use the inverse to solve the system

$\begin{array}{rrrrr}

7x_1&+3x_2&=-9\\

-2x_1&+x_2&=10

\end{array}$

$\begin{bmatrix}

\frac{1}{13}&-\frac{3}{13} \\ \\ \frac{2}{13}& \frac{7}{13} \end{bmatrix}

\begin{bmatrix}

-9\\ \\ 10

\end{bmatrix}

=

\begin{bmatrix}

-3\\ \\ 4

\end{bmatrix}$

the thing I could not get here without a calculator is $A^{-1}$