Question

What value of c is the rational expression below equal to zero? x-4/x-6

Answer 1

Answer: x=4

Steps: (I am assuming your question has a typo in it and by "c" you meant "x")

The rational expression equals zero

$\frac{x-4}{x-6}=0$

only when the numerator equals 0 (the denominator cannot ever be zero):

$x-4 = 0 \\x = 4$

and that happens only for x=4