PLLZZZZZZZ HELP I WILLL GIVE BRAINLIEST TO THE FIRST ONE TO ANSWER

Answer:
5 is the highest/greatest common factor
Step-by-step explanation:
For this, we'll factor it out:
=> 10a-25+5b
Taking 5 common
=> 5(2a-5+b)
Since All are divisible by 5, So 5 is the highest common factor.