simple row operation

Question

anonymous · Answer

I am unclear as how they got the last row, in the last matrix. how did they covert row:
 0 -11 -8 -3 0 1 to 0 1 1 6 -3 1.

thanks!

tkhunny · Answer

The new $R_{3}$ is the old $R_{3} - 3R_{2}$.

I am delighted to see this.  Most would go straight to some fraction, either 11ths or 4th.  Excellent, really excellent.  Find other ways to obtain a unit pivot!!  Or, at least, delay the use of fractions as long as possible.   Don't be afraid of the fractions, just don't use them when they only make it harder.

anonymous · Answer

awesome!. thanks man

anonymous · Answer

ye no caculators in the exam. so really got to use your head (or yours in this case :)