Trouble Using a Cas Calculator

[Finalshine]

Im Using a Cas Calculator to work out the Following Equation

x+11 2(x+14x)
------- = ---------
3 9

Now i no the Answer is -5 but when putting the following Equation in my Calculator i keep comimg up with


11
x= ----
9


Just looking for a bit of Help if any one can help me at all.. thanks Matt

[hypervalent_iodine]

Are you sure it equals -5? I worked it out manually and came to the same answer as your calculator and substituting -5 in for x gives 2 = -16.67 which obviously is incorrect.

[Finalshine]

 

 

 

this is the equation im doing, but my text book says its -5

Edited March 9, 2014 by Finalshine

[John]

Textbooks often contain typos. You should solve the equation by hand and see what you find.

 

At the very least, try plugging in -5 and then 11/9, as hypervalent_iodine did, and see which value results in a true statement.

[Unity+]

I also got 11/9.

 

(x+11)/3=2(x+14x)/9

 

(x+11)/3=2(15x)/9

 

(11/9+11)/3=2(15(11/9))/9

 

(11/9+99/9)/3=2(55/3)/9

 

110/9/3 = 110/3/9

 

110/27 = 110/27

[imatfaal]

Hang on Hang on. What sort of text book writes 30x as 2(x+14x)?!

 

I would bet a pound to a penny that it is not the answer which is wrong but the equation - either in the printing of the text or in the transcription

 

[latex]\frac{x+11}{3}=\frac{2(x+14x)}{9}[/latex]

 

is awful similar to

 

[latex]\frac{x+11}{3}=\frac{2(x+14)}{9}[/latex]

 

which is a much more normal way of writing things

 

[latex]\frac{x+11}{3}=\frac{2(x+14)}{9} [/latex]

 

[latex]\frac{9(x+11)}{3}=2(x+14) [/latex]

 

[latex]3(x+11) = 2(x+14)[/latex]

 

[latex]3x +33 = 2x +28[/latex]

 

[latex]3x-2x = 28-33[/latex]

 

[latex]x = -5[/latex]

[Unity+]

Hang on Hang on. What sort of text book writes 30x as 2(x+14x)?!

 

I would bet a pound to a penny that it is not the answer which is wrong but the equation - either in the printing of the text or in the transcription

 

[latex]\frac{x+11}{3}=\frac{2(x+14x)}{9}[/latex]

 

is awful similar to

 

[latex]\frac{x+11}{3}=\frac{2(x+14)}{9}[/latex]

 

which is a much more normal way of writing things

 

[latex]\frac{x+11}{3}=\frac{2(x+14)}{9} [/latex]

 

[latex]\frac{9(x+11)}{3}=2(x+14) [/latex]

 

[latex]3(x+11) = 2(x+14)[/latex]

 

[latex]3x +33 = 2x +28[/latex]

 

[latex]3x-2x = 28-33[/latex]

 

[latex]x = -5[/latex]

I was originally thinking that the book was going into simplification(combining like terms) because it was weird how a textbook would present the equation as such. Good eye, I must say.