Posted by Karla on Monday, April 9, 2012 at 9:05am.
I'm having a hard time with this problem. The book tells you the answer is 5, but I don't know how they got there.
log(x+25)= 1+ log(2x7)

Math  Steve, Monday, April 9, 2012 at 11:58am
recall that log 1 = 10
log(x+25) = log(10) + log(2x7)
log(x+25) = log(10(2x7))
x+25 = 10(2x7)
x+25 = 20x  70
19x = 95
x = 5
check:
log(30) = 1 + log(3) = log(10)+log(3) = log(30)