Question

This matrix represents a system of equations. When fully row reduced, what will x equal? Assume the first column represents x.

1 3 -3 2
0 1 3 1
0 0 1 2


A. 23 B. -1
C. 11 C. 2

Answer 1

Let the second column be y and the third column be z
so the third row tells us that
z=2
Then the second row says.
y+3z=1
y+6=1
y=-5

And now to htre first row

x+3y-3z=2
x -15-6 =2
x-21 =2
x=23