Question 677587
Let x=the certain number; 5x=5 times the certain number
Sooooo
5x-189=(1/2)x subtract 5x from each side
-189=-5x+(1/2)x
-4.5x=-189
x=42-----------the certain number
CK
(5*42)-189=(1/2)*42
210-189=21
21=21

Hope this helps---ptaylor