so we see the two line of the same length of 14, which tells us that the lengths of 5x and 7x-8 have to be the same length. so we know we can set them equal to each other. Often times that's the key to math problems , finding where you can set things equal.
5x = 7x-8 ( subtract 5x from both sides and then add 8 to both sides )
8 = 2x ( divide both sides by 2 )
4 = x
nice this looks right too , both sides add to 20 :)
