Question

hello..
how to solve these:

1. 2x+y-z=2
x+2y+4z=1
5x+y-7z=4

2. 3/x + 4/y + 6/z = 1
9/x + 8/y - 12/z = 3
9/x - 4/y + 12/z = 4

3. x+y+z=0
y+z-2w=-5
2x-y+3w=9
x+3z-w=-1

4. 2x-y+z-w =5
2y-z+2w=-4
x+y-3w=0
3y+2z-2w=1

? Help me please ..

Answer 1

@dan815 - can you help me with these? :)

Answer 2

question 2....>>>>> http://www.wolframalpha.com/input/?i=3%2Fx%2B4%2Fy%2B6%2Fz%3D1+%3B+9%2Fx%2B8%2Fy-12%2Fz%3D3%3B+9%2Fx-4%2Fy%2B12%2Fz%3D4


question 3..>>>>> http://www.wolframalpha.com/input/?i=x%2By%2Bz%3D0%3B+y%2Bz-2w%3D-5%3B+2x-y%2B3w%3D9%3B+x%2B3z-w%3D-1


question 4....>>>>> http://www.wolframalpha.com/input/?i=2x-y%2Bz-w+%3D5%3B+2y-z%2B2w%3D-4%3B+x%2By-3w%3D0%3B+3y%2B2z-2w%3D1


question 1 is attached file

Answer 3

@binary3i .. thank you very much .. :)) thank you thank you .. :))