jenna is correct
when the brackets are expanded you get
12x + 20y + 8z + 3x - 3z
simplify that to get 15x + 20y + 5z
when factorised, you find a HCF (highest common factor) in this case 5, and divide them all by it. 5 is then placed outside the bracket to create Jennas answer of
5(3x + 4y +z)