# Linear combination problem from linear algebra

Express the column matrix $b$ as a linear combination of the columns of $A$. (Use $A_1$, $A_2$, and $A_3$ respectively for the columns of A.)

\begin{align} A&=\begin{pmatrix}-2 &-5 &4\\3 &-3&5\end{pmatrix}\\b&=\begin{pmatrix}11\\28\end{pmatrix}\end{align}

• (-1) "This question does not show any research effort." – TMM Apr 15 '13 at 9:06

• @user2153126, if you are suggesting that [-1 -3 1] is an answer then it's wrong. You can verify this yourself by multiplying. Also, to get an answer in a different form, simply replace the $b=0$ step with your choice of pivot. – Inquest Apr 15 '13 at 6:26