3. Write equations for two functions of even symmetry with 3 x-intercepts, two of which are x=1 and x=-1 (both multiplicity 1 ).

Step 1 ：An even function is symmetric about the y-axis, which means that $f(x) = f(-x)$.

Step 2 ：Given that the function has x-intercepts at x=1 and x=-1, we know that the function must be 0 at these points. Therefore, the function must have factors of $(x-1)$ and $(x+1)$.

Step 3 ：Since the function is even, it must also have a x-intercept at x=0 to maintain symmetry about the y-axis. Therefore, the function must also have a factor of $x$.

Step 4 ：Thus, one possible function is $f(x) = x(x-1)(x+1)$.

Step 5 ：However, we need two functions. To get another function, we can simply multiply the first function by any non-zero constant. For example, if we multiply by 2, we get $f(x) = 2x(x-1)(x+1)$.

Step 6 ：So, the two functions of even symmetry with 3 x-intercepts at x=1, x=-1 and x=0 are $\boxed{f(x) = x(x-1)(x+1)}$ and $\boxed{f(x) = 2x(x-1)(x+1)}$.