SOLUTION: Which is the first incorrect step to solving {{{ log(x^2-4x)-logx=log2? }}} Step 1:{{{ x^2-4x-x=6 }}} Step 2:{{{ x^2-5x-6=0 }}} Step 3:{{{ (x-6)(x+1)=0 }}} Step 4:

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Which is the first incorrect step to solving {{{ log(x^2-4x)-logx=log2? }}} Step 1:{{{ x^2-4x-x=6 }}} Step 2:{{{ x^2-5x-6=0 }}} Step 3:{{{ (x-6)(x+1)=0 }}} Step 4:       Log On


   

Question 612460: Which is the first incorrect step to solving
+log%28x%5E2-4x%29-logx=log2%3F+
Step 1:+x%5E2-4x-x=6+
Step 2:+x%5E2-5x-6=0+
Step 3:+%28x-6%29%28x%2B1%29=0+
Step 4: ++++x=6+
I need to know which is the first incorrect step.
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
The answer x=6 is correct, but the very first step is wrong.
Here is how to solve it:

         log(x²-4x)-log(x) = log(2)

      log[x(x-4)] - log(x) = log(2)

log(x) + log(x-4) - log(x) = log(2)

                  log(x-4) = log(2)
 
                       x-4 = 2

                         x = 6

This shows that it is possible to do a problem wrong and get the right answer.
Edwin