+0  
 
0
1217
5
avatar+46 

12^x-2=20 ? Explain please

 May 23, 2014

Best Answer 

 #1
avatar+129849 
+8

Is the 12 being raised to the power of "x" or the power of (x-2) ??

 May 23, 2014
 #1
avatar+129849 
+8
Best Answer

Is the 12 being raised to the power of "x" or the power of (x-2) ??

CPhill May 23, 2014
 #2
avatar+19 
0

my answer is 24

 May 24, 2014
 #3
avatar+118667 
+5

I'll answerthe question asked but you do need to use brackets AllSmilesAlways to make your meaning clear.

$$\begin{array}{rll}
12^x-2&=&20\\\\
12^x&=&22\\\\
log(12^x)&=&log22\\\\
xlog12&=&log22\\\\
x&=\frac{log22}{log12}\\\\
x&\approx &1.244 \mbox{ correct to 3 decimal places}
\end{array}$$

 

Can someone please tell me why this did not align properly?

\begin{array}{rll}

12^x-2&=&20\\\\

12^x&=&22\\\\

log(12^x)&=&log22\\\\

xlog12&=&log22\\\\

x&=&\frac{log22}{log12}\\\\

x&\approx &1.244 \mbox{ correct to 3 decimal places}

\end{array}

 May 24, 2014
 #4
avatar+893 
+5

You missed the & in front of \frac.

 May 24, 2014
 #5
avatar+118667 
0

Thanks you Bertie.    

 May 24, 2014

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