Question 504080
Assume the problem is:
{{{f/2}}} - 19 = -17 
Add 19 to both sides
{{{f/2}}} - 19 + 19 = -17 + 19
{{{f/2}}} = +2
multiply both sides by 2 to get rid of the denominator, this leaves us with
f = 4
:
:
Check this in the original problem replacing f with
{{{4/2}}} - 19 = -17 
2 - 19 = -17
-17 = -17; confirms our solution