Respuesta :

The description for an Isosceles trapezoid is that it has two opposites parallel, the two other opposites legs are equal and also the diagonals are equal.
side 1 = AB = 6y-6
side 2 = BC = 4y -7
side 3 = CD = 7y-12

When AB & CD are the two opposites and their measurement are equal. We will be we have:
AB=CD
6y-6 = 7y -12
Perform transposition method:
7y-6y=12-6
1y = 6
y=6

The answer for the "y" value is "6".