The terms of the polynomial are 45b and 27. You can start finding the GCF by finding the GCf of 45 and 27.
The factors of 45 are 1, 3, 5, 9, 15, and 45.
The factors of 27 are 1, 3, 9, and 27.
Their highest common factor is 9. Since 27 doesn't have a variable attached to it, the GCF can only be a number. So, the GCF of the terms is 9.