SOLUTION: My son is trying to complete his summer math booklet for Sophomore year. I have no idea how to solve these. They have no available online help and he has never learned them. Please

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Question 768196: My son is trying to complete his summer math booklet for Sophomore year. I have no idea how to solve these. They have no available online help and he has never learned them. Please help. If you can show him, he will be able to figure out the rest. Here are two examples:
1) sqrt(3n+12)=sqrt(n+8) and
2) An ambulance left the hospital and drove south. 3 hours later a police car left driving 42 k/h faster attempting to catch up to the ambulance. The officer caught up after 2 hours. Find the average speed of the ambulance.
Thank you in advance!

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
1) sqrt%283n%2B12%29=sqrt%28n%2B8%29
Since both sides are enclosed in a square root, just square both sides & you have:
3n + 12 = n + 8
3n - n = 8 - 12
2n = - 4
n = -2
Substitute -2 for n in the original equation to confirm our answer
sqrt%283%28-2%29%2B12%29=sqrt%28-2%2B8%29
sqrt%28-6%2B12%29=sqrt%286%29
sqrt%286%29=sqrt%286%29; which is obviously true
and
2) An ambulance left the hospital and drove south.
3 hours later a police car left driving 42 k/h faster attempting to catch up to the ambulance.
The officer caught up after 2 hours.
Find the average speed of the ambulance.
Let s = the speed of the ambulance
then
(s+42) = speed of the police car
:
When the police catch the ambulance, they will have traveled the same dist.
Write a distance equation ; dist = speed * time
5s = 2(s+42)
5s = 2s + 84
5s - 2s = 84
3s = 84
s = 84/3
s = 28 k/h is the speed of the ambulance
:
:
Confirm this find the actual dist each traveled, should be the same
5(28) = 140 km
2(28+ 42) = 140 km