NEED HELP! GIVING POINTS!

Using the side-splitter theorem, daniel wrote a proportion for the segment formed by luke segment de. what is ec?

Ineed with math stuff it involves graphs

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.