Given: f(x)=x2−1f(x) = x^2 - 1f(x)=x2−1 Substitute x=0x = 0x=0: f(0)=(0)2−1=0−1=−1\begin{aligned} f(0) &= (0)^2 - 1 \\ &= 0 - 1 \\ &= -1 \end{aligned}f(0)=(0)2−1=0−1=−1 f(0)=−1\boxed{f(0) = -1}f(0)=−1