Question

The row-reduced form of a system of three linear equations in three variables is given by this matrix. How many solutions does the system have?

Answer 1

B. infinite solutions along a line

Explanation:

The matrix is equivalent to the equations ...

x = 2

y = 9

0z = 0 . . . . . . true for any z

This tells you the solutions are ...

(x, y, z) = (2, 9, z)

This defines a line parallel to the z-axis.