Question

Just an answer and simple explanation! Thank you.

Answer 1

15

Explanation:

If CD and DE equal, then x+6 = 4x -21

So if you subtract x from both sides and plus 21 to both sides, that would be 3x = 27. Divide by 3 on both sides and you get 9.

Plug in x+6 with 9 and you get 15.