|You can't put "multiple formulas" in one cell. Strictly speaking, you can't even get a formula to do "multiple things".|
A formula can only do one thing: return a result
Now, it may perform multiple calculations on the way to returning that result, but in the end it really only did 1 thing: returned a result.
That said, you really don't want =(M5-K5) to be the first step, you actually want that to be the last step.
If I understand your request correctly, you want to return M5-K5-1 if any of the three words are in Columns F and return M5-K5 if not.
The IF function is designed to do a "logical test" and return one result if the test returns TRUE and an different result if the test returns FALSE.
=IF(logical_test, value_if_true, value_if_false)
In your case, the logical test is:
Does Column F contain "good" or "exact" or "ranch"?
We can determine if that is the case by "counting" the number of times each word occurs. If the count is greater than 0 for any of those words, then at least one of those words exists in Column F.
The value_if_true is (M5-K5-1)
The value_if_false is (M5-K5)
Putting that all together we get:
COUNTIF(F:F, "ranch" )>0),M5-K5-1,M5-K5)
Note: the formula has been split into 2 lines to make it easier to read.