Answer:
(e-f)(2c+d)
Step-by-step explanation:
group the first 2 terms:
(2ce-2cf) and (de-df)
take out the greatest common factor from each group:
2c(e-f) and d(e-f)
times the duplicated bracket by the two terms on the outside of the bracket:
(e-f)(2c+d)
hope this helps :)