cross multiply

combine like terms

take natural log

Note that this is not what you posted, you said when x = 0, f(x) > 1/2. But we have that this is not true. It can be verified by plugging in 0 and seeing that your initial criteria are not correct:

and since 1/2 is not greater than 1/2, your initial criteria should have been either

a. Show that for all

or

a. Show that for all