Hello there!
To solve this equation for the variable k, you must isolate k so that it is set equal to a value. To start, first multiply both sides by 7 to get rid the 7 in the denominator:
7(-k/7)=7(-4)
This would result in -k=-28.
The next step would be to divide both sides by -1 as we still need to fully isolate the value of k:
-k/-1=-28/-1
This would result in your answer, k=28
Now, to check that 28 is the correct value of k, plug 28 back into the original equation to see if you get a result of -4=-4:
-(28)/7=-4
-28/7=-4
-4=-4
Now that you have confirmed k=28, you can conclude that that would be your answer.
Hope this helps!