Functions and their Graphs

Question

Let g be the function defined by g(x) = −x² + 8x. Find a + g(a) and 1/g(a)

Answer 1

just change x to a to get

g(a) = -a^2 + 8a

then make that the denominator of a fraction, just invert it

1/g(a) = 1/(-a^2 + 8a)