Answer: x = 4
Step-by-step explanation:
An isosceles trapezoid has two opposite sides (the bases) parallel, and the two other sides (the legs) are of equal length.
So, since the two legs are of equal length, you only need to use the information of the two legs:
Leg WX: 6x + 5
Leg: YZ: 8x - 3
Leg WX = Leg YZ => 6x + 5 = 8x - 3
6x + 5 = 8x - 3
=> 8x - 6x = 5 + 3
=> 2x = 8
=> x = 8 / 2
=> x = 4