Posted by Kari on .
Hi this is a dimensional analysis problem,I want to solve for x.
300x^2 16.667x^3+(7200)=0
after getting
300x^2 16.667x^3=7200
I really don't know what to do.
Plz help.

Math (Dimensional Analysis) 
Reiny,
This is very effective online webpage.
I simply entered the equation in the form
300x^2 16.667x^37200 = 0
http://www.wolframalpha.com/input/?i=300x%5E2+16.667x%5E37200+%3D0
It gave my 3 real answers and the corresponding gram of
f(x) = 300x^2 16.667x^37200 
Math (Dimensional Analysis) 
drwls,
Let the 16.667 be treated at 16 2/3. Then
900 x^2 50 x^3 21600 = 0
One root of that equation is exactly x = 6. Call it a lucky guess.
Divide the cubic by (x6) to get an easily solved quadratic, for the other two roots. It can be reduced to
x^2 120 x 72 = 0