Answer:
50%
Step-by-step explanation:
Since it was $6, half of $6 is $3. So, $6 to $9 is a $3 difference, which is 1/2. 1/2 is a 50% increase.
Answer:
$8.87 per pound
Step-by-step explanation:
The greatest common factor (gcf) is 6.
It's dependent on the context. A book may ask you to find the f'(x) of a function and you may have to use a u sub in your problem which requires you to find the dy/dx of what you substitute. So in this case both would be used.