The value of the missing length is 20
Let the missing length be x
From Parallel lines and transversal theorem, we have that
If three or more parallel lines intersect two transversals, then they cut off the transversals proportionally.
Then, we can write that

∴ 
x = 20
Hence, the value of the missing length is 20
Learn more here: brainly.com/question/24258397
Answer:
-7x + 5
Step-by-step explanation:
2(4x + 1) - 3(5x - 1)
8x + 2 - 3(5x-1)
8x + 2 - 15x + 3
8x + 5 - 15x
-7x + 5
Hope it helped !
Adriel
Im sorry wish i could help but the equation is a little confusing give me a few moments and i will figure out the answer okay?