Answer:
+1 and -1
Explanation:
The function in this problem is:

First of all, we have to define the domain of the function, which is the set of values of x for which the function is defined.
In order to find the domain, we have to require that the denominator is different from zero, so

which means:

So the domain is all values of x, except from 4 and -7.
Now we can solve the problem and find the zeros of the function. The zeros can be found by requiring that the numerator is equal to zero, so:

This is verified if either one of the two factors is equal to zero, therefore:

and

We see that both values are part of the domain, so they are acceptable values: so the zeros of the function are +1 and -1.