The Greatest Common Factor (GCF) is very important when factoring. Later on, you will forget to pull out a GCF and the answer will be wrong. Always look for a GCF before doing anything.
Let's try factoring these:
a.) 
The greatest common factor of this expression is 9, because it is the maximum number that both can go into. Let's solve.
This is the simplest this expression can get. This would be your final answer. Let's try the other one.
b.) 
The GCF of this one is 12. Let's simplify it.
This is also the simplest you can get it. You can do nothing further. So, your final answers are:
a.)
b.)
The findings 20/40 vision in the right eye implies that when Tina is standing at a distance of 20 feet away from the eye chart, she will be able to read with her right eye what a person with normal vision can read from a distance of 40 feet away from the eye chart. Also, Tina has got 20/20 vision in the left eye, this implies that when Tina stands 20 feet from the eye chart , she will be able to read with her left eye what a person with normal vision can read from 20 feet away with the left eye. In conclusion this implies that Tina has normal vision in her left eye but a decreased vision in her right eye.
Answer:
And the circumference is given by this formula:
And replacing the value fo r we got:
And then the final answer would be 62.8 units for the circumference.
Step-by-step explanation:
For this case we know that the area for a circle is given by:
And we know that 
We can find the radius from the previous formula like this:
And the circumference is given by this formula:
And replacing the value fo r we got:
And then the final answer would be 62.8 units for the circumference.
