Question 46292
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log10 4th root of (y^3/20x^5)
          _________
         /   y<sup>3</sup> 
log<sub>10</sub>\ 4/  -------
      \/    20x<sup>5</sup>

Write the 4th root as the 1/4th power
           _ 
     |¯ y<sup>3</sup>  |1/4 
log<sub>10</sub>|------|
     |_20x<sup>5</sup> |
           ¯ 

Use the rule log<sub>b</sub>a<sup>c</sup> = c·log<sub>b</sub>a

               _ 
         |¯ y<sup>3</sup>  | 
1/4·log<sub>10</sub>|------|
         |_20x<sup>5</sup> |




Use the rule log<sub>b</sub>(a/c) = log<sub>b</sub>a - log<sub>b</sub>c

1/4[log<sub>10</sub>y<sup>3</sup> - log<sub>10</sub>(20x<sup>5</sup>)]

Use the rule log<sub>b</sub>(ac) = log<sub>b</sub>a + log<sub>b</sub>c

1/4[log<sub>10</sub>y<sup>3</sup> - (log<sub>10</sub>20 + log<sub>10</sub>x<sup>5</sup>)]

Remove the parentheses

1/4[log<sub>10</sub>y<sup>3</sup> - log<sub>10</sub>20 - log<sub>10</sub>x<sup>5</sup>]

Use the rule log<sub>b</sub>a<sup>c</sup> = c·log<sub>b</sub>a on 1st and 3rd terms:

1/4[3·log<sub>10</sub>y - log<sub>10</sub>20 - 5·log<sub>10</sub>x]

Write the 20 as (2·10)

1/4[3·log<sub>10</sub>y - log<sub>10</sub>(2·10) - 5·log<sub>10</sub>x]

Use the rule log<sub>b</sub>(ac) = log<sub>b</sub>a + log<sub>b</sub>c on middle term

1/4[3·log<sub>10</sub>y - (log<sub>10</sub>2 + log<sub>10</sub>10) - 5·log<sub>10</sub>x]

Remove the parentheses:

1/4[3·log<sub>10</sub>y - log<sub>10</sub>2 - log<sub>10</sub>10 - 5·log<sub>10</sub>x]

Use the rule log<sub>b</sub>b = 1 on third term:


1/4[3·log<sub>10</sub>y - log<sub>10</sub>2 - 1 - 5·log<sub>10</sub>x]

Edwin</pre>