A few terms from the given LU factorization of A are missing. Find them. $\left[\begin{array}{ccc} 1 &0 &0\cr 5 &1 &0\cr a &9 &1\cr \end{array}\right] \left[\begin{array}{cc} 1 &-6\cr 0 &b\cr 0 &0\cr \end{array}\right] = \left[\begin{array}{cc} 1 &c\cr 5 &-29\cr -6 &45\cr \end{array}\right]$
$a=$
$b =$
$c =$