Solve by completing the square

Question

x^2-18x=10

Could you please explain this process. I have read through the text over and over and I just do not understand the process.

Answer 1

x^2 - 18x + 81 = 10 + 81
(x-9)^2 = 91
x-9 = ± √91
x = 9 ± √91

Answer 2

Thank for the solution but I still don't understand how the process works.

Answer 3

You need to take the middle term (which is 18), take half of it (9) and square it (81). You then add that number to both sides.

Answer 4

Thank you!