Evaluate the function at the given values:

f (-1/2) = 2x-5

You have the original function as 2x-5

and you are given the value of x to be - 1/2

Therefore, all you have to do is substitute the value of x in the function and calculate it as follows:

f (-1/2) = 2 (-1/2) - 5 = - 1 - 5 = - 6

The answer would be - 6