1. ## Exponent equation help

Hi I'm new to the forum so apologies if I've posted in the wrong section or my title is misleading.

My maths isn't great but I have a problem to solve using a pressure drop formulae 0.3=(800*160*300^2)/(7d^5.31)

So I need to solve for d to figure out my pipe diameter and I've got this far...

2.1d^5.31=11520000000 (Multiplying both sides by 7d^5.31)

d^5.31=5485714285.71 (Dividing both sides by 2.1)

This is as far as I've got and I'm unsure on the next step I wondered if somebody could point me in the right direction please? (Or point out I've gone wrong already if so)

2. ## Re: Exponent equation help

$\dfrac{(800)(600)(300^2)}{7d^{5.31}} = 0.3$

$480000\cdot 90000 = 2.1 d^{5.31}$

$\dfrac{1296000000000}{7} = d^{5.31}$

$d = \left(\dfrac{1296000000000}{7}\right)^{1/5.31} = 132.416$

3. ## Re: Exponent equation help

Originally Posted by Satnav
0.3=(800*160*300^2)/(7d^5.31)
This makes it a little easier:

u = 800*160*300^2

u / (7d^5.31) = 3 / 10

RULE: if a^p = x, then a = x^(1/p) : as Sir Romsek showed you