Answer:
3(2p+7)
Explanation:
To find this, you have to find a number that, taken out of 6 and 21, can be taken out to become the factor product.
The GCF is 3, because 3 can go into 6 twice and into 21 7 times.
So,
3(2p+7)
When multiplied to check our work, we get 6p+21, so this is the correct equation.
Hope this helps :)