It works because 7 x 9 x 10 is the same thing as 7 x 90, since 9 x 10 is just 90. So basically he is just writing more but the answer will still be the same.
Answer:
The error is at step (3) .
The correct step (3) will be,

=
[by using the laws of indices]
All other steps are correct.
Step-by-step explanation:
The error is at the step (3) , because the student has tried to prove the quotient rule of logarithms by using the property i.e., 'The quotient rule of logarithm' itself , i.e. ,by assuming the property does hold before proving it. So, the proof is fallacious.
The correct step (3) will be,

=
[by using the laws of indices]
All other steps are correct.
Answer:
nine hours
Step-by-step explanation:
48 divided by 6 is 8 and 8 times 9 is 72
Answer:
thank you very much
Step-by-step explanation:
Since it takes one hour to fly 230 miles, and we are looking for the number of hours, we can divide the number of miles we are given by the speed. In this case, we would divide 1380 by 230 to get 6. This means it would take 6 hours for the plane to fly 1380 miles.