Question

shortcut for solving a system of linear equations if I only need to solve for one of the variables?

Answer 1

so I need to solve this system of equations
\[A-B-C=0\]\[C-D-F=0\]\[B+D-E=0\]\[2C+20F=1\]\[2C-3B+7D=0\]\[20F-7D-5E=0\]
I can put these in an augmented matrix and row reduce to solve for all the variables, but the truth is I only need to find out what A is. What is the quickest way I can do this by hand?

Answer 2

cramer's rule

Answer 3

http://en.wikipedia.org/wiki/Cramer's_rule

Answer 4

I don't see how cramers rule will be any faster?

Answer 5

all you have to do is solving two determinants .. as i see it it is much faster