The correct answer for the first one is ⇒ f (x + 1)
A reflection across the x axis changes f(x) to -f(x) = g(x)
So.....
Multiplying f(x) by -1 on both sides, we have that
-f(x) = - ( x^2 + 5)
-f(x) = -x^2 - 5
And for -f(x), we can write g(x)
so
g(x) = -x^2 - 5
Look at the graph here, NSS : https://www.desmos.com/calculator/zq0ozrsd5b
Notice if we "flipped" the red graph - f(x) - across the x axis.....it would coincide perfectly with the blue graph, g(x)