Question 1203611
<pre>
x+4y-6z=-1
2x-y+2z=-7
-x+2y-4z=5

I've said it many times before and I will continue to say it!! Something is seriously wrong with that
MATHLOVER "character." I don't think this person is capable of learning to do math the way it should be
done, without taking the student through "hell," especially when some math problems are so easy to solve. 

  x + 4y - 6z = - 1 ----- eq (i)
 2x -  y + 2z = - 7 ----- eq (ii)
- x + 2y - 4z = 5 ------- eq (iii)

Now, looking at the system of equations, since she's so "bent" on using substitution, then why not 
solve eq (i) for x, since its coefficient is 1, or eq (ii) for y, since its coefficient is - 1, or even 
eq (iii) for x, since it too has a coefficient of - 1? She instead chose to solve the one equation, # 1,
for y - with a coefficient of 4 - that produces a fractional expression for y, which in most cases 
can cause errors and sheer torment to most students! 

Why does this person keep doing these things? Is this how a tutor - a mere quasi-tutor, in her case - helps others?

One doesn't have to even bother applying substitution as it's quite obvious/clear as daylight that when eqs
(i) & (iii) are combined/added, x is immediately eliminated, which means that one or another pair of equations would 
need to be manipulated in order to eliminate x too. A pair of equations in "y" and "z" would then remain to be solved!</pre>