Your friend lives 4 miles west of your house. grocery store is 15 mi east of friends house. beach is 2 miles west of grocery store. when your are at the beach how far from home are you

I'm not completely sure but if you think your friend is 15 miles from it and you are four miles from your friend and you are actually closer to the store you would 15-4=11 then add 2 more miles because that is the distance from the grocery store so you should get 13 miles from home.

You would be 7 miles away from home. 
4 to the left
15-4=9
9-2=7

First subtract 10 from both side
y^2+6y-16=0
(y+8)(y-2)=0
-8 and 2