Q1) Use Gauss-Jordan method to determine solution to following system of equations:

3x - 5y - 2z = -9

-4x + 3y + z = 11

8x - 5y + 4z = 6

1. (-2,3, -5)
2. (-3, -2,5)
3. (4,2,1)
4. (-5,1, -2)

2)  U.S. exports to China have grown since 1991.  In 1991, about 10 billion dollars of goods were exported to China.  By 2001, this amount had grown to 19 billion dollars. Write linear equation explaining number of exports each year, with x = 91 representing 1991 and x = 101 representing 2001.

i) y = 1.11x - 108.3

ii) y = 0.9x - 71.9

iii) y = 0.9x + 82

iv) y = 1.11x - 71.9

Q3) Use echelon method to determine solution to following system of equations:

2x + y + z = 9

-x - y + z = 1

3x - y + z = 9

i) (2,1,4)

ii) (4,1,2)

iii) (3,0,3)

iv) (-4,3,0)