Question

Which is a rational function?

a. y=√x-3
b. y=x²-3x+5
c. y=x-5/x
d.y=5

Answer 1

certainly y=5 looks rational

Answer 2

from the word rational, "ratio", which among the options has a fraction?
it's C

Answer 3

A rational function is defined as the quotient of two polynomial functions.
Grouping symbols are important in mathematics because they provide clarity.

While, c. y=x-5/x
appears to be the answer, it is not clear if c) mean y = (x - 5)/x or y = x - (5/x) which could be converted to y = (x^2-5) / x. I suppose that either interpretation leads to a rational function although grouping symbols would dissolve the ambiguity here.

Answer 4

@directrix. correct