#### Answer

1 zero

#### Work Step by Step

The number of zeros of the function is determined by the degree of the polynomial. The degree is the high value exponent of x. For example:
y = x is a first degree since x has an exponent of 1.
y = $x^{2}$ is a second degree polynomial since x has an exponent of 2.
The number of zeros is the degree of the polynomial.
We first need to expand this polynomial to evaluate:
f(x) = $(t - 1)^{2}$ - $(t + 1)^{2}$
f(x) = $t^{2}$ - 2t + 1 - $t^{2}$ - 1 - 2t
f(x) = -4t
In this example, the highest exponent (degree of the polynomial) on the x is 1, so there is 1 zero.