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If $2^{20} - 2^{19} = 2^x$, what is the value of $x$?$$If $2^{20} - 2^{19} = 2^x$, what is the value of $x$?$$

Dabae  Jun 28, 2015

Best Answer 

 #2
avatar+89840 
+11

Vey nice, Sir-Emo-Chappington   ......here's another way to do this

 

2^20 - 2^19  =  2^x       factor the left side........

 

2^19 (2 - 1)  = 2^x

 

2^19 (1)  = 2^x

 

2^19  = 2^x      .....and it's obvious that x = 19

 

 

CPhill  Jun 28, 2015
 #1
avatar+423 
+11

2x = 220 - 219

Another way of reading this is:

2x = 220 - 220-1

Which equates to:

2x = 220 - (220 / 2)

Now, we get the situation of "x - (x/2) = (x/2)". This means 2x is a half of 220, which is another way of saying:

2x = 219

x = 19

Sir-Emo-Chappington  Jun 28, 2015
 #2
avatar+89840 
+11
Best Answer

Vey nice, Sir-Emo-Chappington   ......here's another way to do this

 

2^20 - 2^19  =  2^x       factor the left side........

 

2^19 (2 - 1)  = 2^x

 

2^19 (1)  = 2^x

 

2^19  = 2^x      .....and it's obvious that x = 19

 

 

CPhill  Jun 28, 2015

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