4a^2+9b^2+25c^2-12ab+20ac-30bc divided by 2a-3b+5c.
As I showed earlier,
4a^2 + 9b^2 + 25c^2 - 12ab + 20ac - 30bc
= (2a-3b+5c)^2
So, divide and you get 2a-3b+5c
4a^2 + 9b^2 + 25c^2 - 12ab + 20ac - 30bc
= (2a-3b+5c)^2
So, divide and you get 2a-3b+5c