Answer
False.
Work Step by Step
Take the quadratic equation $f(x)=(x-1)^2$, or $f(x)=(x-1)(x-1)$. To find the solutions, set $f(x)$ to $0$ and get $$(x-1)(x-1)=0$$ $$x-1=0,x-1=0$$ $$x=\{1,1\}=1$$ Therefore, this function only has one zero, disproving the statement.