How do you solve #log_[4] (5x +1) - log_ [4] (x + 2) =1#?
1 Answer
Apr 12, 2016
x = 7
Explanation:
Using the following
#color(blue)" laws of logarithms " #
#• log x - logy = log(x/y) #
#• log_b a = n hArr a = b^n #
# log_4((5x+1)/(x+2)) = 1 rArr (5x+1)/(x+2) = 4^1 = 4# solve :
#(5x+1)/(x+2) = 4 # cross-multiply : 5x+1 = 4(x+2)
hence 5x + 1 = 4x+8
# rArr x = 7 #
