My math professor presented this problem .. nobody was able to complete it for the test the day prior, so this is a review.

AB ∩ CD = {E}

AB = 15

CD = 20

The video cuts off before finishing the problem .. but chances are if you can understand thus far, you can solve the remaining algebra:

Since you have 4y=x, substitute it into the equation to become this:

60 -4(4y) = 20 -y

60 -16y = 20 – y

40 = 15y

40/15 = y

8/3 = y

Then, substitute the y into the 4y=x to get x:

4(8/3) = x

32/3 = x