Use matrices and Gauss-Jordan elimination to solve systems of linear equations

Question

The matrix

1	0	4	0
0	1	−6	−1
0	0	−5	5

can be reduced in the row echelon form

1	0	0	a
0	1	0	b
0	0	1	c

where a, b, and c are real numbers. Find a. (Enter an exact number.)

a = ____

Answer 1

Set Row3 = Row3/-5

Set Row1 = Row1 - 4Row3

Set Row2 = Row2 + 6Row3

[1 0 0 4]

[0 1 0 -7]

[0 0 1 -1]

a = 4