Hello
You cannot find then analyze a graph in parametric mode, but you solve you t in terms of x and y in terms of x, and then graph the function and solve like a normal function.
Luckily, you have a CAS, so solve in terms of variables is easy.
For instance, one method is
solve(x=x1(t),t)
y1(right side of above answer)
And then enter that into f1(x), or just type f1(x):= y1(right side of above answer)
Hope this helps