9. answer is 12
10. answer is 3.5
11. answer is 23
Answer:
I also need some help!!!!
The arnold family arrived at the beach at 10:30 A.M.
10:30
Add 3 hours and 3/4 minutes to that
3/4 = 75% of 60
.75 * 60 = 45
3 hours and 45 minutes
10:30 >> 3 hours more = 1:30
1:30 + 45 mins = 2:15
Answer would be: They left at 2:15
(a-b) X (a+b)
= aXa - bXa +aXb -bXb (distributing)
Now, cross product of a vector with itself = 0
so, aXa = 0, bXb = 0
Also, aXb = - bXa
so,
(a-b) X (a+b) = 0 + aXb + aXb + 0
= 2aXb
hence, proved :)
