Math
posted by Kari .
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, Thursday, November 24, 2011 at 11:27am
This is very effective online webpage.
I simply entered the equation in the form
300x^2 16.667x^37200 = 0
It gave my 3 real answers and the corresponding gram of
f(x) = 300x^2 16.667x^37200
Hi, I know I already posted this, i already used Wolfram Alpha before, but in this case they don't show the step by step solution, so I know the answers but I don't know how to get them. I'll appreciate it if I can be told how to solve this problem.

Ok Kari, let's have a closer look at your equation.
the 16.667 appears to be a rounding of 16.6666....
or 16 2/3 which would be 50/3
so your equation is
300x^2  (50/3)x^2  7200 = 0
times 2
900x^2  50x^3  21600 = 0
divide by 50
18x^2  x^3  432 = 0
I now cheated and used Wolfram again and found an exact answer of x = 6
( Or we could have used x = ±1, ±2, ±3, ±4, ±6, etc, that is, factors of 432, and eventually we could find that x=6 works)
so x6 is a factor, and by synthetic division,
18x^2  x^3  432 = (x6)(x^2 + 12x + 72)
so using the quadratic formula on
x^2  12x  72  0
x = (12 ± √432)/2 = (12 ± 12√3)/2
= 6 ± 6√3
when I answered before I took the equation exactly as you typed it.
Respond to this Question
Similar Questions

Conversions!
1. The price of gold is 200 dollars/oz. How much did 1 g of gold cost that day? 
chemistry
How do I solve this question using dimensional analysis? 
Chemistry
I am studying dimensional analysis right now, and I get most of it, but I don't understand how to solve this problem: 5982 ox./pt=BLANK g/ml. I'm not sure how you do dimension analysis with units per units like this one. Thanks!! 
math
There are two machines that produce aluminum cans. The newer machine can produce 7200 cans in 200 minutes. It takes the older machine 300 minutes to produce that many cans. If the two machines work together, how long will it take them … 
PreAlgebra
Can someone show me how to solve this problem step by step? 
Algebra
Use P= 7200+300x2x^2 p= profit x selling price question: Determine the selling price when 90% of the maximum possible profit is earned 
PreAlgebra Checkk
1. Convert the rate using dimensional analysis. 30 miles/hour = _______ feet/second a. 0 b. 44 c. 43 d. 2 answer: b 2. Convert the rate using dimensional analysis. 16 feet/second = _____ yards/minute a. 240 b. 120 c. 10 d. 320 answer: … 
MathHelp please?
Michael owns 300 shares of a certain stock. Suppose the price of the stock drops by $4 per share. Write a multiplication equation to find the change in Michael's investment. I put 300x(300x[4]) is that right? 
Math (Dimensional Analysis)
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. 
chemistry
How would this problem be worked using dimensional analysis?