i think wat u do is
since the function is even (the top one), the only way is if each of the two on the left are also even bc thats the only way that makes sense
f(-x) + g(-x)= f(x) + g(x), since each are even, their addition will be symmetrical about the y and also even
however if they were both odd f(-x) + g(-x)= -f(x) - g(x) which sum to give -(f(x) + g(x)) which in a similar manner would also be odd if u think abt it graphically as they are symmetrical about the origin
so for this question, f(x-1) and f(1-x) must both be even,
also we get that f(1-x) = f[-(x-1)] = f(x-1)
So u have 2[f(x-1)] = 2x^2 + 8
so if [f(x-1)] = x^2 + 4 (this is shifted right by one unit)
the original function would have been shifted to the left by one unit compared to f(x-1) which would shift the parabola left meaning it wouldnt be even anymore and hence it would be neither
watch this be completely wrong and hence i will drop to standad 1 maths by next term