April 26, 2011
Warm-up Problem: April 15, 2011.
Solve the system of equations
using Gaussian elimination.
x - 2y + z = 7
2x - 2y - z = 3
3x - 4y
= 10
3x - 5y + z = 14
2x - 2y - z = 3
5x - 7y
= 17
3x - 4y = 10 x (7) 21x - 28y = 70
5x - 7y = 17 x (-4) -20x + 28y = -68
x = 2
3(2) - 4y = 10
2 - 2(-1) + z = 7
6 - 4y = 10
4+z=7
-4y = 4
z=3
y = -1
Check the other two equations.
3(2) - 5(-1) + 3 = 14
6 + 5 + 3 = 14
2(2) - 2(-1) - 3 = 3
4+2-3=3
1
April 26, 2011
Warm-up Problem: April 26, 2011.
2