Answer:
AD=35
Explanation:
The difference between FJ-GH is equal to the difference between EK-FJ
Lets call this difference "D"
so
(7x+2)-(8x-7)=D
simplifying
7x+2-8X+7=D
-x+9=D
(10x-1)-(7x+2)=D
simplifying
10x-1-7x-2=D
3x-3=D
now D=D so
-x+9=3x-3
12=4x
x=3
solving each known line equation for x:
8(3)-1=17
7(3)+2=23
10(3)-1=29
The line gets longer each time by 6
AD=EK+6=35