The one mistake is -27-10 they put -17 as the answer but it is actually -37.
It is suppose to be:
8x-27-10-6x=15
Rephrase it: 8x-6x-27-10=15
Combine like terms: 2x-37=15
add 37 to each side of the equal sign
(which cancels out the -37): 2x=52
then divide the two numbers by 2: 2x/2=52/2
which then gives you x=26...
you can plug in 26 where you see x in the equation to check your work