The first term as a variable, the second doesn't so there isn't any variable that can be factored out.
The first number is 15 = 5 x 3
The second number is 27 = 3 x 3 x 3
There is one common factor, 3.
The greatest common factor of 15x and 27 is 3.
The only number that can be factored out of 15x + 27 is 3; 3(5x + 9)
The first term as a variable, the second doesn't so there isn't any variable that can be factored out.
The first number is 15 = 5 x 3
The second number is 27 = 3 x 3 x 3
There is one common factor, 3.
The greatest common factor of 15x and 27 is 3.
The only number that can be factored out of 15x + 27 is 3; 3(5x + 9)