Ln integration

Hello, I keep getting different answers for the following integration: f'(x) = 2/(10x + 25), so f(x) = 1/5 ln(10x + 25) (via reverse chain rule),
but if first splitting the denominator into 5(2x + 5) and then using the reverse chain rule, why do I get 1/5 ln(2x+5). Maybe I am just very sleepy, am I reverse chain rule-ing wrong?

Youve not written the integration constant in each case. Does that explain things?

It is a definite (improper) integral between infinity and 1. The mark scheme used the latter solution and got a different answer to mine.

When you evaluate them both using the limits, do you get the same answer?
Whether its definite/indefinite doesnt really change the hint, how are they "different"?

Well I have redone the question both ways and came to the right solution, yay. So both 1/5 ln(2x + 5) + c1 and 1/5 ln(10x + 25) + c2 are correct, and give the same solution when limits are applied. Thank you.

Do you understand why? Think about the basic log rule
ln(ab) = ln(a) + ln(b)

I did think about the following... 1/5 ln(10x + 25) = 1/5 ln(5(2x + 5)) = 1/5 ln(5) + 1/5 ln(2x + 5), but logically it's not making sense to me beyond that... Could you elaborate?

I did think about the following... 1/5 ln(10x + 25) = 1/5 ln(5(2x + 5)) = 1/5 ln(5) + 1/5 ln(2x + 5), but logically it's not making sense to me beyond that... Could you elaborate?