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The question was:

x (3x- 2x + 5)

 

My working out+answer:

=3x- 2x+ 5

=x+ 5

 

Textbook answer:

=3x- 2x+ 5

 

Now I understand how they got that answer. When I multiply x with 3x^2, the exponent changes from 3x^2  ---> 3x^3.

 

But then doesn't that conflict with one of the indices laws?:

(am)x  =  am × x

 

So applying that rule:

▪x is to the power of 1 (since anything to the power of 1 is itself)

▪3x^2 is to the power of 2

 

• so it would be 3x2×1 

• that's how I got 3x3

 

Why does it not work?

 Nov 15, 2018

Best Answer 

 #1
avatar+18332 
+2

x * x^2   = x^(2+1) = x^3

 

this is NOT  (x^m)^n      this  is   x^m  *  x^n  = x^(m+n)    

     so  x^1 * x^2 = x^(2+1) = x^3

 Nov 15, 2018
edited by ElectricPavlov  Nov 15, 2018
 #1
avatar+18332 
+2
Best Answer

x * x^2   = x^(2+1) = x^3

 

this is NOT  (x^m)^n      this  is   x^m  *  x^n  = x^(m+n)    

     so  x^1 * x^2 = x^(2+1) = x^3

ElectricPavlov Nov 15, 2018
edited by ElectricPavlov  Nov 15, 2018

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