Solve for x or find x

we have to find x to solve the equation

the answer is x= 4

AB and CD are the same length

8x-1 =31

8x=32

x=4

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.