Question 32929
[(4x-1)/(x^2+5x-14)]=[1/(x-2)]-[2/(x+7)]
Factor where you can and get a common denominator on the right side as follows:
[(4x-1)/(x+7)(x-2)]= [(x+5)/(x-2)(x+7)]
Both denominators are the same so equate the numerators to get:
4x-1=x+5
3x=6
 x=2

1)y=-5x-2
  y=-3x
Substitute to get:
  -3x=-5x-2
   2x=-2
    x=-1
Substitute again to get:
  y=(-3)(1)
  y=3
Solution: (-1,3)

2)
a)3x-y=5
b)-4x+y=-5
Rewrite as:
a)y=3x-5
b)y=4x-5
This is a contradiction.  There is no solution 
for this system of equations.  The lines are 
parallel and do not intersect.

3)Rewrite as follows:
  2x-y+0z=-1
  2x+0y+z=-6
  0x+3y-z=7
And use Cramer.
I get x=-1/4; y=1/2; z=-11/2
Cheers,