Question 1001255
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Let logb 5 = X and logb 7 = y. Use the log laws to write each expression in terms of X and Y. 
a) logb 35 
b) logb 49 
c) logb (625/7)
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a)  {{{log(b, (35))}}} = {{{log(b, (5*7))}}} = {{{log(b, (5))}}} + {{{log(b, (7))}}} = x + y.


b)  {{{log(b, (49))}}} = {{{log(b, (7*7))}}} = {{{log(b, (7))}}} + {{{log(b, (7))}}} = y + y = 2y.


c)  {{{log(b, (625/7))}}} = {{{log(b, (625))}}} - {{{log(b, (7))}}} = {{{log(b, (5^4))}}} - {{{log(b, 7)}}} = {{{4*log(b, (5))}}} = 4x - y.