Algebra Queston Help

[walker8476]

Could some show me step by step how to solve for F. I'm doing something wrong with the algebra and I don't know what it is.

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \mbox{ f x }\, \frac{347}{0.066}}\)

\(\displaystyle F\, =\, 0.970\)

 

[wjm11]

Could some show me step by step how to solve for F. I'm doing something wrong with the algebra and I don't know what it is.

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \mbox{ f x }\, \frac{347}{0.066}}\)

\(\displaystyle F\, =\, 0.970\)

Comments:
1) F is not the same as f; they are different variables. Choose one and stick with it.
2) If you are in Algebra, is is a good idea to stop using "x" to indicate multiplication because it is too easily confused with the variable x. It is better to group things with parentheses to indicate multiplication: e.g.: (f)(347/.006) means f times (347/.006).
3) Using a calculator, I get an answer of f = .969341; this would round to f = .969, not f = .970 .
4) You are likely getting a wrong answer due to an "order of operations" error in using your calculator. That is just a guess since you did not show us your work. You did not even tell us what answer you did get.

 

[walker8476]

Comments:
1) F is not the same as f; they are different variables. Choose one and stick with it.
2) If you are in Algebra, is is a good idea to stop using "x" to indicate multiplication because it is too easily confused with the variable x. It is better to group things with parentheses to indicate multiplication: e.g.: (f)(347/.006) means f times (347/.006).
3) Using a calculator, I get an answer of f = .969341; this would round to f = .969, not f = .970 .
4) You are likely getting a wrong answer due to an "order of operations" error in using your calculator. That is just a guess since you did not show us your work. You did not even tell us what answer you did get.

No I think I'm getting the wrong answer because I don't know how to do algebra very well. I have attached my pitiful attempt at answering the question.

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \mbox{f }\, \left(\frac{347}{0.066}\right)}\)

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \frac{347f}{0.066f}}\)

\(\displaystyle \mbox{Common denom}\mbox{inator}\)

\(\displaystyle 0.083\, *\, 0.066f\, =\, 0.005478f\)

\(\displaystyle \displaystyle{0.005478f \left(\frac{423}{0.083}\right)\, =\, 0.005478f\left(\frac{347f}{0.066}\right)}\)

\(\displaystyle 27.918f\, =\, 28.801f\)

I don't know what to do next.

 

[wjm11]

No I think I'm getting the wrong answer because I don't know how to do algebra very well. I have attached my pitiful attempt at answering the question.

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \mbox{f }\, \left(\frac{347}{0.066}\right)}\)

\(\displaystyle \displaystyle{\frac{423}{0.083}\, =\, \frac{347f}{0.066f}}\)

\(\displaystyle \mbox{Common denom}\mbox{inator}\)

\(\displaystyle 0.083\, *\, 0.066f\, =\, 0.005478f\)

\(\displaystyle \displaystyle{0.005478f \left(\frac{423}{0.083}\right)\, =\, 0.005478f\left(\frac{347f}{0.066}\right)}\)

\(\displaystyle 27.918f\, =\, 28.801f\)

I don't know what to do next.

Thank you for showing your work. It will allow us to make rapid progress.

Your error was a simple one, and it occurred when you distributed f.

Recognize that f is the same as f/1, so when we multiply it times the fraction (347/.066), f should only be multiplied with the numerator (and not with the denominator).

Making this correction and following your approach, we would have

27.918 = 28.801f

The final step would be to divide both sides by 28.801 and we'd have:

f = .969341

Note: While your method was fine (using the common denominator) there is a more straightforward method. When we start the problem, f is being multiplied by the fraction (347/.066). If we simply multiply both sides of the equation by the inverse (or reciprocal) of this fraction, we will have isolated f in a single step:

(423/.083)(.066/347) = f(347/.066)(.066/347)

.969341 = f

Hope that helps.

 

[walker8476]

I get it now

Hope that helps.

Yes I see my error now. I like the inverse method, so much easier. Thank you so much, you saved me another day trying to nut out what I was doing wrong.