Final answer:
To solve for x and make quadrilateral ABCD a parallelogram, set up the equation AB = CD and solve for x.
Step-by-step explanation:
To solve for x and make quadrilateral ABCD a parallelogram, we need to use the properties of parallelograms. One property is that opposite sides of a parallelogram are equal in length. So, we can set up the equation AB = CD, which gives us 6x - 5 = 3x + 17. By solving this equation, we find that x = 6.