Posted by **Elllie** on Sunday, September 18, 2011 at 5:03pm.

Please check answer and help with one of them:

1. check please

car in an accident speed of car is the s, d is length of skid=30 feet

f is coefficient=0.5

use formula to find

s=sqaure root of 30*f*d

My answer is 21.21 because I took square root of 30(0.5)(30)

2. this one is baffling to me-how do I do this one-3 times square root of (x+1) is less than or equal to 7 Please help-Thank you

- Pre-Calc -
**Elllie**, Sunday, September 18, 2011 at 5:04pm
I posted earlier but no one answered so I was hoping if I reposted someone could help

- Pre-Calc -
**Reiny**, Sunday, September 18, 2011 at 5:14pm
3√(x+1) ≤ 7

9(x+1) ≤ 49

9x+9 ≤49

9x ≤ 40

x ≤ 40/9

of course in √(x+1) , x >-1 or else the √ is undefined.

so -1 ≤ x ≤ 40/9

- Pre-Calc-reiny please recheck -
**Elllie**, Sunday, September 18, 2011 at 6:01pm
Thank you for showing me the second one-just one question-is #1 correct the way I did it?

Thank you

- Pre-Calc -
**Reiny**, Sunday, September 18, 2011 at 6:06pm
correct if you formula was

s = √(30fd)

- Pre-Calc -
**Ellie**, Sunday, September 18, 2011 at 6:21pm
The 30fd was under the square root sign-thank you

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