Question

LINEAR ALGEBRA HELP PLZ!!
http://puu.sh/bB2vr/61b1c4f28b.png

Answer 1

damn proofs

Answer 2

:c

Answer 3

If \(A\) is invertible, then \(A^{-1}\) exists.
\[ A^{-1}A \vec{x}=A^{-1}\vec{b}\\
I\vec{x}=A^{-1}\vec{b}\\
\vec{x}=A^{-1}\vec{b}\]

Suppose \(\vec{y}\) and \(\vec{x}\) are solutions. Then going through the same procedure, you find. \(\vec{x}=A^{-1}\vec{b}\) and \(\vec{y}=A^{-1}\vec{b}\). WHich implies \(\vec{x}=\vec{y}\), hence there is only a unique solution.

Answer 4

good stuff @kirbykirby

Answer 5

recommended to be boosted to level 99

Answer 6

Lol. I think I still need more medals/fans to get there haha