Don't forget that your first project is due upon return from Spring Break,
too. If you need any help, please contact me (but I'll be out of touch from
Sunday evening until Wednesday of Spring Break).
Homework 2.4/2.5 returned: graded
#13, section 2.4
Remember: the proof is "if and only if" -- you have to prove both directions
A invertible => B,C invertible
B,C invertible => A invertible
B and C don't have to be the same size (but they're both square)
Don't row-reduce further to solve
Ly=b
or
Ux=y
Back-solve! You're wasting time and energy.
Read questions carefully! You were to also solve
Ax=b directly by rref.