ok so assuming the 0 means minus from typing problems
x^2-10x=-8
to completet the square
make sure the term in front of x^2 is 1
that is correct
then take 1/2 of the term in front of the x term and square it
-10/2=-5, (-5)^2=25
add that to both sides
x^2-10x+25=17
answer is the first equation