More Rational Exponents!
posted by Brady .
1. The optimal height h of the letters of a message printed on pavement is given by the formula . Here, h= (0.00252d^(9/4))/e d is the distance of the driver from the letters and e is the height of the driverâ€™s eye above the pavement. All of the distances are in meters. Explain how to find h when d = 90 m and e = 1.4 m.
2.Simplify.
(27a^(6) )^(2/3)
For 2 I got 1/(9a^4 )as my answer, but can someone again please check this.
For 1 I really do not know, I have been trying to figure out for a while.
Please check and help me for 1, and please help with 2. 1 is from another thing, but no one has answered it.
I will appreciate the help. Also, please try to answer these two as soon as possible.

I did mean to put "For 1 I really do not know, I have been trying to figure it out for a while." instead of what I put. Just saying this, so no one will get confused at that point.

Is anyone there? I'm still here, and will be until it gets answered. I will still appreciate it if you guys can answer these.

For 1, I think the answer is this:
First, you replace the variables with 90 and 1.4 to get this equation: (0.00252∙〖90〗^(9/4))/1.4. Next, you turn the 〖90〗^(9/4)into ∜(〖90〗^9 ). Then, I turn ∜(〖90〗^9 )into 3∜(〖10〗^9 ), and simplify 3∜(〖10〗^9 )to 9∜10. Next, I divide o.oo252 by 1.4 to get 0.0018. Then, my next equation is: 0.0018∙9∜10. Finally, I multiply 0.0018 and 9 together to get 0.0162, and my final answer is 0.0162∜10
Is my answer correct? Please check it to make sure that it is correct or not? Also, if it is incorrect, please help me correct my mistakes. I will appreciate it if any of you guys do. 
If anyone can answer or help me for these two problems, please do. I will appreciate it even more if you can answer and/or check the problems as soon as possible. I have been waiting and trying to answer it for a long time. My mom wants me to get my lesson done on this topic today, and I am stuck at this point, which is really close to the end. Also, thank you if anyone can help or answer these two problems.