Question

I need to know the answer ASAP please

Answer 1

By observing the points you can learn a lot about a function. Concretely $f(x)$ passes through $(1,1)$ but $g(x)$ passes through $(1,-\frac{1}{2})$ that should give you a hint that $g(x)=-\frac{1}{2}x^2$.

Hope this helps :)