Assuming A, B, and D are co-linear, and in that order, we have

(5y - 4) + (7y + 3) = (20y - 9)

12y - 1 = 20y - 9 (collect terms)

8 = 8y (add 9-12y to both sides)

1 = y (divide both sides by 8)

AB = 1, BD = 10, AD = 11

(5y - 4) + (7y + 3) = (20y - 9)

12y - 1 = 20y - 9 (collect terms)

8 = 8y (add 9-12y to both sides)

1 = y (divide both sides by 8)

**The value of y is 1.**AB = 1, BD = 10, AD = 11