How do you solve using gaussian elimination or gauss-jordan elimination, x+y+z=2x+y+z=2, 2x-3y+z=-112x3y+z=11, -x+2y-z=8x+2yz=8?

1 Answer
Jun 1, 2018

The solution is ((x),(y),(z))=((1/3),(10/3),(-5/3))

Explanation:

The augmented matrix is

A=((1,1,1,|,2),(2,-3,1,|,-11),(-1,2,-1,|,8))

The pivot is in the the first column of the first row

Perform the operations on the rows

R2larrR2-2R1 and R3larrR3+R1

=>, ((1,1,1,|,2),(0,-5,-1,|,-15),(0,3,0,|,10))

Make the pivot in the second column

R2larr(R2)/(-5)

=>, ((1,1,1,|,2),(0,1,1/5,|,3),(0,3,0,|,10))

Eliminate the second column

R1larrR1-R2 and R3larrR3-3R2

=>, ((1,0,4/5,|,-1),(0,1,1/5,|,3),(0,0,-3/5,|,1))

Make the pivot in the third column

R3larr(R3xx-5/3)

=>, ((1,0,4/5,|,-1),(0,1,1/5,|,3),(0,0,1,|,-5/3))

Eliminate the third column

R1larr(R1-4/5xxR3) and R2larr(R2-1/5xxR3)

=>, ((1,0,0,|,1/3),(0,1,0,|,10/3),(0,0,1,|,-5/3))

The solution is

((x),(y),(z))=((1/3),(10/3),(-5/3))