Answer:
A root of f(x) is x=5
Step-by-step explanation:
If (x-5) is a factor of f(x), then 5 is a root.
If (x+5) is a factor of f(x), then -5 is a root.
So we are only given that (x-5) is a factor of f(x), so we only know that x=5 is a root.
This is by factor theorem. It says if (x-c) is a factor then f(c)=0 which means c is a root of f(x) because it makes the expressions equal to 0.
First prime factorize the number:
25 = 5 × 5
75 = 3 × 5 × 5
Then find the GCF:
GCF(25, 75)
= 5 × 5
= 25
±70
