As per the given question, the expression of the function is as:
Now, as per the definition of zeros, the zero is that value of x which when plugged into the function should make the function zero (it is also called "making the function vanish"). <u>In our case, plugging in "zero values" of x should make the numerator zero without making the denominator zero.</u> Now, if we plug in the given values of x, which are x=-1, x=2 and x=4 in the function we see that the <u>numerator does not become a zero but the denominator does</u>.
Thus, x=-1, x=2 and x=4 are not the zeros of the function and therefore, Sue is wrong. However, we do have discontinuities at the aforementioned values of x because the denominator becomes a zero at those points and as per the definition of a discontinuity the denominator should be a zero at that point. Therefore, Ed is correct.