See:
http://www.jiskha.com/display.cgi?id=1294279972
Are you allowed to do this
2log(x-1) =log(x+1)
2 (x-1)=(x+1)
x=3
Please help :)
3 answers
Some mathteacher published a book some time ago listing all the silly solutions that students had produced.
It actually had it this way
2log(x-1) =log(x+1)
(2log(x-1))/log = (log(x+1))/log , then the log/log canceled
2(x-1) = (x+1)
2x - 2 = x+1
x = 3, which by sheer coincidence is the right answer.
It actually had it this way
2log(x-1) =log(x+1)
(2log(x-1))/log = (log(x+1))/log , then the log/log canceled
2(x-1) = (x+1)
2x - 2 = x+1
x = 3, which by sheer coincidence is the right answer.
My teacher showed us this one:
64/16
= (6)4/1(6) [cancel the 6]
= 4/1
= 4
gets the right answer, but the wrong way.
64/16
= (6)4/1(6) [cancel the 6]
= 4/1
= 4
gets the right answer, but the wrong way.