e graph of fx can also be described by the equation gx a log
     e graph of f(x) can also be described by the equation g(x) a log, x. Find the value of a  
  
  Solution
15) f(x) = log8(x) ; g(x) = alog2(x)
f(x) = logx/log8 = logx/3log2 = (1/3)log2(x)
So, a = 1/3
17) g(x) = alog2(x) +k
(1/4 , -9) and (16, -6)
Plug each point and form equations:
(1/4 , -9)
-9 = alog2(1/4) +k
-9 =a log(2^-2)/log2 +k
-9 = -2a +k ----(1)
(16, -6)
-6 = alog2(16) +k
-6 = alog(2^4)/log2 +k
-6 = a*4 +k ----(2)
solve 1 and 2 to get a and k : -9 +6 = -2a -4a
-6a= -3 ; a = 1/2
-6 = (1/2)*4 +k ; k = -6 -2 = -8
So, g(x) = (1/2)log2(x) - 8

