How would you solve (4k+5)(k+1)=0?

(4k + 5) (k + 1) = 0

Before you rush off and start trying to do complicated things with that equation,
put your pencil down, fold your hands in your lap, and sit and look at it for a while.
Keep looking at it until a little voice yells out "Hey !  That's a true statement if
either (4k + 5) is zero  or  (k+1) is zero.  THEN go to work on it.

(4k + 5 = 0)
4k = -5
k = -5/4

(k + 1 = 0)
k = -1

And there are the two solutions to that equation.