Answer:
(x+10)(x-10)
Explanation:
The factor for x+10 is x+10 itself.
(x+10) = x+10
(x+10) occurs 1 time.
The factor for x-10 is x-10 itself.
(x-10) = x-10
(x+10) occurs 1 time.
The LCM of x+10, x-10 is the result of multiplying all factors the greatest number of times they occur in either term.
(x+10)(x-10)