Cut one root and pour concrete around another?

Update: The root on the right is one inch diameter. The fence post needs to be where that root is. Safe to cut this root despite it s size and since the nearest tree is 10 feet away? Also that large root you see is also ten feet from the nearest tree so can we pour concrete around and under it to help secure the post. Thanks.
Update 2: What is up with the system. All we can do is post the question and no details or photo. Then we have to click on update to add details and can not post photos. Our photo is under 30Kb. Can we pour concrete above and around the large root which is 2.5 to 3 inch in diameter? And ok to cut the one inch root and not... show more What is up with the system. All we can do is post the question and no details or photo. Then we have to click on update to add details and can not post photos. Our photo is under 30Kb. Can we pour concrete above and around the large root which is 2.5 to 3 inch in diameter? And ok to cut the one inch root and not damage the tree which is 10 feet away.
Update 3: Cutting a large root like that won't harm the tree? which is already leaning toward the house at an angle of about 60 degrees. But the root is 10 feet from the tree.
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