Answer:
(6)
Step-by-step explanation:
Since it is an isosceles trapezoid the length of the two legs (i.e. AB = 5y-10 and CD = 2y+8) are equal. In other words,
5y - 10 = 2 y + 8
Subtract 2y from each side:
5y - 2y - 10 = 8
Now add 10 to each side
5y - 2y - 10 + 10 = 8 + 10 =>
3y + 0 = 18 =>
3y = 18 =>
y = 6